@inproceedings{GrundmannBauerBorchersetal.2019, author = {Grundmann, Jan Thimo and Bauer, Wlademar and Borchers, Kai and Dumont, Etienne and Grimm, Christian D. and Ho, Tra-Mi and Jahnke, Rico and Koch, Aaron D. and Lange, Caroline and Maiwald, Volker and Meß, Jan-Gerd and Mikulz, Eugen and Quantius, Dominik and Reershemius, Siebo and Renger, Thomas and Sasaki, Kaname and Seefeldt, Patric and Spietz, Peter and Spr{\"o}witz, Tom and Sznajder, Maciej and Toth, Norbert and Ceriotti, Matteo and McInnes, Colin and Peloni, Alessandro and Biele, Jens and Krause, Christian and Dachwald, Bernd and Hercik, David and Lichtenheldt, Roy and Wolff, Friederike and Koncz, Alexander and Pelivan, Ivanka and Schmitz, Nicole and Boden, Ralf and Riemann, Johannes and Seboldt, Wolfgang and Wejmo, Elisabet and Ziach, Christian and Mikschl, Tobias and Montenegro, Sergio and Ruffer, Michael and Cordero, Federico and Tardivel, Simon}, title = {Solar sails for planetary defense \& high-energy missions}, series = {IEEE Aerospace Conference Proceedings}, booktitle = {IEEE Aerospace Conference Proceedings}, doi = {10.1109/AERO.2019.8741900}, pages = {1 -- 21}, year = {2019}, abstract = {20 years after the successful ground deployment test of a (20 m) 2 solar sail at DLR Cologne, and in the light of the upcoming U.S. NEAscout mission, we provide an overview of the progress made since in our mission and hardware design studies as well as the hardware built in the course of our solar sail technology development. We outline the most likely and most efficient routes to develop solar sails for useful missions in science and applications, based on our developed `now-term' and near-term hardware as well as the many practical and managerial lessons learned from the DLR-ESTEC Gossamer Roadmap. Mission types directly applicable to planetary defense include single and Multiple NEA Rendezvous ((M)NR) for precursor, monitoring and follow-up scenarios as well as sail-propelled head-on retrograde kinetic impactors (RKI) for mitigation. Other mission types such as the Displaced L1 (DL1) space weather advance warning and monitoring or Solar Polar Orbiter (SPO) types demonstrate the capability of near-term solar sails to achieve asteroid rendezvous in any kind of orbit, from Earth-coorbital to extremely inclined and even retrograde orbits. Some of these mission types such as SPO, (M)NR and RKI include separable payloads. For one-way access to the asteroid surface, nanolanders like MASCOT are an ideal match for solar sails in micro-spacecraft format, i.e. in launch configurations compatible with ESPA and ASAP secondary payload platforms. Larger landers similar to the JAXA-DLR study of a Jupiter Trojan asteroid lander for the OKEANOS mission can shuttle from the sail to the asteroids visited and enable multiple NEA sample-return missions. The high impact velocities and re-try capability achieved by the RKI mission type on a final orbit identical to the target asteroid's but retrograde to its motion enables small spacecraft size impactors to carry sufficient kinetic energy for deflection.}, language = {en} } @article{LoebSchartnerDachwaldetal.2012, author = {Loeb, Horst Wolfgang and Schartner, Karl-Heinz and Dachwald, Bernd and Ohndorf, Andreas and Seboldt, Wolfgang}, title = {Interstellar heliopause probe}, series = {Труды МАИ}, journal = {Труды МАИ}, number = {60}, publisher = {Moskauer Staatliches Luftfahrtinstitut (МАИ)}, address = {Moskau}, pages = {2 -- 2}, year = {2012}, abstract = {There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array.}, language = {en} } @inproceedings{OhndorfDachwaldSeboldtetal.2011, author = {Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang and Schartner, Karl-Heinz}, title = {Flight times to the heliopause using a combination of solar and radioisotope electric propulsion}, series = {32nd International Electric Propulsion Conference}, booktitle = {32nd International Electric Propulsion Conference}, pages = {1 -- 12}, year = {2011}, abstract = {We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks' parameter set. Based on a parameter space study, in which the number of thrust units, the unit's specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the escape direction is restricted to the heliosphere's "nose".}, language = {en} } @inproceedings{BorggraefeDachwald2010, author = {Borggr{\"a}fe, Andreas and Dachwald, Bernd}, title = {Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients}, series = {2nd International Symposium on Solar Sailing}, booktitle = {2nd International Symposium on Solar Sailing}, pages = {1 -- 6}, year = {2010}, abstract = {Solar sails provide ignificant advantages over other low-thrust propulsion systems because they produce thrust by the momentum exchange from solar radiation pressure (SRP) and thus do not consume any propellant.The force exerted on a very thin sail foil basically depends on the light incidence angle. Several analytical SRP force models that describe the SRP force acting on the sail have been established since the 1970s. All the widely used models use constant optical force coefficients of the reflecting sail material. In 2006,MENGALI et al. proposed a refined SRP force model that takes into account the dependancy of the force coefficients on the light incident angle,the sail's distance from the sun (and thus the sail emperature) and the surface roughness of the sail material [1]. In this paper, the refined SRP force model is compared to the previous ones in order to identify the potential impact of the new model on the predicted capabilities of solar sails in performing low-cost interplanetary space missions. All force models have been implemented within InTrance, a global low-thrust trajectory optimization software utilizing evolutionary neurocontrol [2]. Two interplanetary rendezvous missions, to Mercury and the near-Earth asteroid 1996FG3, are investigated. Two solar sail performances in terms of characteristic acceleration are examined for both scenarios, 0.2 mm/s2 and 0.5 mm/s2, termed "low" and "medium" sail performance. In case of the refined SRP model, three different values of surface roughness are chosen, h = 0 nm, 10 nm and 25 nm. The results show that the refined SRP force model yields shorter transfer times than the standard model.}, language = {en} } @inproceedings{DachwaldKahleWie2007, author = {Dachwald, Bernd and Kahle, Ralph and Wie, Bong}, title = {Head-on impact deflection of NEAs: a case study for 99942 Apophis}, series = {Planetary Defense Conference 2007}, booktitle = {Planetary Defense Conference 2007}, pages = {1 -- 12}, year = {2007}, abstract = {Near-Earth asteroid (NEA) 99942 Apophis provides a typical example for the evolution of asteroid orbits that lead to Earth-impacts after a close Earth-encounter that results in a resonant return. Apophis will have a close Earth-encounter in 2029 with potential very close subsequent Earth-encounters (or even an impact) in 2036 or later, depending on whether it passes through one of several less than 1 km-sized gravitational keyholes during its 2029-encounter. A pre-2029 kinetic impact is a very favorable option to nudge the asteroid out of a keyhole. The highest impact velocity and thus deflection can be achieved from a trajectory that is retrograde to Apophis orbit. With a chemical or electric propulsion system, however, many gravity assists and thus a long time is required to achieve this. We show in this paper that the solar sail might be the better propulsion system for such a mission: a solar sail Kinetic Energy Impactor (KEI) spacecraft could impact Apophis from a retrograde trajectory with a very high relative velocity (75-80 km/s) during one of its perihelion passages. The spacecraft consists of a 160 m × 160 m, 168 kg solar sail assembly and a 150 kg impactor. Although conventional spacecraft can also achieve the required minimum deflection of 1 km for this approx. 320 m-sized object from a prograde trajectory, our solar sail KEI concept also allows the deflection of larger objects. For a launch in 2020, we also show that, even after Apophis has flown through one of the gravitational keyholes in 2029, the solar sail KEI concept is still feasible to prevent Apophis from impacting the Earth, but many KEIs would be required for consecutive impacts to increase the total Earth-miss distance to a safe value}, language = {en} } @inproceedings{GrundmannBodenCeriottietal.2017, author = {Grundmann, Jan Thimo and Boden, Ralf and Ceriotti, Matteo and Dachwald, Bernd and Dumont, Etienne and Grimm, Christian D. and Lange, Caroline and Lichtenheldt, Roy and Pelivan, Ivanka and Peloni, Alessandro and Riemann, Johannes and Spr{\"o}witz, Tom and Tardivel, Simon}, title = {Soil to sail-asteroid landers on near-term sailcraft as an evolution of the GOSSAMER small spacecraft solar sail concept for in-situ characterization}, series = {5th IAA Planetary Defense Conference}, booktitle = {5th IAA Planetary Defense Conference}, pages = {30 Seiten}, year = {2017}, language = {en} } @incollection{Dachwald2010, author = {Dachwald, Bernd}, title = {Solar sail dynamics and control}, series = {Encyclopedia of Aerospace Engineering}, booktitle = {Encyclopedia of Aerospace Engineering}, publisher = {Wiley}, address = {Hoboken}, doi = {10.1002/9780470686652.eae292}, year = {2010}, abstract = {Solar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo-)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.}, language = {en} } @inproceedings{SeboldtDachwald2003, author = {Seboldt, Wolfgang and Dachwald, Bernd}, title = {Solar sails for near-term advanced scientific deep space missions}, series = {Proceedings of the 8th International Workshop on Combustion and Propulsion}, booktitle = {Proceedings of the 8th International Workshop on Combustion and Propulsion}, pages = {14 Seiten}, year = {2003}, abstract = {Solar sails are propelled in space by reflecting solar photons off large mirroring surfaces, thereby transforming the momentum of the photons into a propulsive force. This innovative concept for low-thrust space propulsion works without any propellant and thus provides a wide range of opportunities for highenergy low-cost missions. Offering an efficient way of propulsion, solar sailcraft could close a gap in transportation options for highly demanding exploration missions within our solar system and even beyond. On December 17th, 1999, a significant step was made towards the realization of this technology: a lightweight solar sail structure with an area of 20 m × 20 m was successfully deployed on ground in a large facility at the German Aerospace Center (DLR) at Cologne. The deployment from a package of 60 cm × 60 cm × 65 cm with a total mass of less than 35 kg was achieved using four extremely light-weight carbon fiber reinforced plastics (CFRP) booms with a specific mass of 100 g/m. The paper briefly reviews the basic principles of solar sails as well as the technical concept and its realization in the ground demonstration experiment, performed in close cooperation between DLR and ESA. Next possible steps are outlined. They could comprise the in-orbit demonstration of the sail deployment on the upper stage of a low-cost rocket and the verification of the propulsion concept by an autonomous and free flying solar sail in the frame of a scientific mission. It is expected that the present design could be extended to sail sizes of about (40 m)2 up to even (70 m)2 without significant mass penalty. With these areas, the maximum achievable thrust at 1 AU would range between 10 and 40 mN - comparable to some electric thrusters. Such prototype sails with a mass between 50 and 150 kg plus a micro-spacecraft of 50 to 250 kg would have a maximum acceleration in the order of 0.1 mm/s2 at 1 AU, corresponding to a maximum ∆V-capability of about 3 km/s per year. Two near/medium-term mission examples to a near-Earth asteroid (NEA) will be discussed: a rendezvous mission and a sample return mission.}, language = {en} } @inproceedings{DachwaldSeboldtHaeusler2002, author = {Dachwald, Bernd and Seboldt, Wolfgang and H{\"a}usler, Bernd}, title = {Performance requirements for near-term interplanetary solar sailcraft missions}, series = {6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century}, booktitle = {6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century}, pages = {9 Seiten}, year = {2002}, abstract = {Solar sailcraft provide a wide range of opportunities for high-energy low-cost missions. To date, most mission studies require a rather demanding performance that will not be realized by solar sailcraft of the first generation. However, even with solar sailcraft of moderate performance, scientifically relevant missions are feasible. This is demonstrated with a Near Earth Asteroid sample return mission and various planetary rendezvous missions.}, language = {en} } @inproceedings{SchartnerLoebDachwaldetal.2009, author = {Schartner, Karl-Heinz and Loeb, H. W. and Dachwald, Bernd and Ohndorf, Andreas}, title = {Perspectives of electric propulsion for outer planetary and deep space missions}, series = {European Planetary Science Congress 2009}, booktitle = {European Planetary Science Congress 2009}, pages = {416 -- 416}, year = {2009}, abstract = {Solar-electric propulsion (SEP) is superior with respect to payload capacity, flight time and flexible launch window to the conventional interplanetary transfer method using chemical propulsion combined with gravity assists. This fact results from the large exhaust velocities of electric low-thrust propulsion and is favourable also for missions to the giant planets, Kuiper-belt objects and even for a heliopause probe (IHP) as shown in three studies by the authors funded by DLR. They dealt with a lander for Europa and a sample return mission from a mainbelt asteroid [1], with the TANDEM mission [2]; the third recent one investigates electric propulsion for the transfer to the edge of the solar system. All studies are based on triple-junction solar arrays, on rf-ion thrusters of the qualified RIT-22 type and they use the intelligent trajectory optimization program InTrance [3].}, language = {en} } @inproceedings{SpurmannOhndorfDachwaldetal.2009, author = {Spurmann, J{\"o}rn and Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang and L{\"o}b, Horst and Schartner, Karl-Heinz}, title = {Interplanetary trajectory optimization for a sep mission to Saturn}, series = {60th International Astronautical Congress 2009}, booktitle = {60th International Astronautical Congress 2009}, isbn = {9781615679089}, pages = {5234 -- 5248}, year = {2009}, abstract = {The recently proposed NASA and ESA missions to Saturn and Jupiter pose difficult tasks to mission designers because chemical propulsion scenarios are not capable of transferring heavy spacecraft into the outer solar system without the use of gravity assists. Thus our developed mission scenario based on the joint NASA/ESA Titan Saturn System Mission baselines solar electric propulsion to improve mission flexibility and transfer time. For the calculation of near-globally optimal low-thrust trajectories, we have used a method called Evolutionary Neurocontrol, which is implemented in the low-thrust trajectory optimization software InTrance. The studied solar electric propulsion scenario covers trajectory optimization of the interplanetary transfer including variations of the spacecraft's thrust level, the thrust unit's specific impulse and the solar power generator power level. Additionally developed software extensions enabled trajectory optimization with launcher-provided hyperbolic excess energy, a complex solar power generator model and a variable specific impulse ion engine model. For the investigated mission scenario, Evolutionary Neurocontrol yields good optimization results, which also hold valid for the more elaborate spacecraft models. Compared to Cassini/Huygens, the best found solutions have faster transfer times and a higher mission flexibility in general.}, language = {en} } @inproceedings{LoebSchartnerDachwaldetal.2007, author = {Loeb, Horst Wolfgang and Schartner, Karl-Heinz and Dachwald, Bernd and Seboldt, Wolfgang}, title = {SEP-Sample return from a main belt asteroid}, series = {30th International Electric Propulsion Conference}, booktitle = {30th International Electric Propulsion Conference}, pages = {1 -- 11}, year = {2007}, abstract = {By DLR-contact, sample return missions to the large main-belt asteroid "19, Fortuna" have been studied. The mission scenario has been based on three ion thrusters of the RIT-22 model, which is presently under space qualification, and on solar arrays equipped with triple-junction GaAs solar cells. After having designed the spacecraft, the orbit-to-orbit trajectories for both, a one-way SEP mission with a chemical sample return and an all-SEP return mission, have been optimized using a combination of artificial neural networks with evolutionary algorithms. Additionally, body-to-body trajectories have been investigated within a launch period between 2012 and 2015. For orbit-to-orbit calculation, the launch masses of the hybrid mission and of the all-SEP mission resulted in 2.05 tons and 1.56 tons, respectively, including a scientific payload of 246 kg. For the related transfer durations 4.14 yrs and 4.62 yrs were obtained. Finally, a comparison between the mission scenarios based on SEP and on NEP have been carried out favouring clearly SEP.}, language = {en} } @inproceedings{DachwaldMengaliQuartaetal.2007, author = {Dachwald, Bernd and Mengali, Giovanni and Quarta, Alessandro A and Macdonald, Malcolm and McInnes, Colin R}, title = {Optical solar sail degradation modelling}, series = {1st International Symposium on Solar Sailing}, booktitle = {1st International Symposium on Solar Sailing}, pages = {1 -- 27}, year = {2007}, abstract = {We propose a simple parametric OSSD model that describes the variation of the sail film's optical coefficients with time, depending on the sail film's environmental history, i.e., the radiation dose. The primary intention of our model is not to describe the exact behavior of specific film-coating combinations in the real space environment, but to provide a more general parametric framework for describing the general optical degradation behavior of solar sails.}, language = {en} } @article{Dachwald2005, author = {Dachwald, Bernd}, title = {Optimization of very-low-thrust trajectories using evolutionary neurocontrol}, series = {Acta Astronautica}, volume = {57}, journal = {Acta Astronautica}, number = {2-8}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, isbn = {1879-2030}, pages = {175 -- 185}, year = {2005}, abstract = {Searching optimal interplanetary trajectories for low-thrust spacecraft is usually a difficult and time-consuming task that involves much experience and expert knowledge in astrodynamics and optimal control theory. This is because the convergence behavior of traditional local optimizers, which are based on numerical optimal control methods, depends on an adequate initial guess, which is often hard to find, especially for very-low-thrust trajectories that necessitate many revolutions around the sun. The obtained solutions are typically close to the initial guess that is rarely close to the (unknown) global optimum. Within this paper, trajectory optimization problems are attacked from the perspective of artificial intelligence and machine learning. Inspired by natural archetypes, a smart global method for low-thrust trajectory optimization is proposed that fuses artificial neural networks and evolutionary algorithms into so-called evolutionary neurocontrollers. This novel method runs without an initial guess and does not require the attendance of an expert in astrodynamics and optimal control theory. This paper details how evolutionary neurocontrol works and how it could be implemented. The performance of the method is assessed for three different interplanetary missions with a thrust to mass ratio <0.15mN/kg (solar sail and nuclear electric).}, language = {en} } @inproceedings{SchoutetensDachwaldHeiligers2021, author = {Schoutetens, Frederic and Dachwald, Bernd and Heiligers, Jeannette}, title = {Optimisation of photon-sail trajectories in the alpha-centauri system using evolutionary neurocontrol}, series = {8th ICATT (International Conference on Astrodynamics Tools and Techniques) 23 - 25 June 2021, Virtual}, booktitle = {8th ICATT (International Conference on Astrodynamics Tools and Techniques) 23 - 25 June 2021, Virtual}, pages = {1 -- 15}, year = {2021}, abstract = {With the increased interest for interstellar exploration after the discovery of exoplanets and the proposal by Breakthrough Starshot, this paper investigates the optimisation of photon-sail trajectories in Alpha Centauri. The prime objective is to find the optimal steering strategy for a photonic sail to get captured around one of the stars after a minimum-time transfer from Earth. By extending the idea of the Breakthrough Starshot project with a deceleration phase upon arrival, the mission's scientific yield will be increased. As a secondary objective, transfer trajectories between the stars and orbit-raising manoeuvres to explore the habitable zones of the stars are investigated. All trajectories are optimised for minimum time of flight using the trajectory optimisation software InTrance. Depending on the sail technology, interstellar travel times of 77.6-18,790 years can be achieved, which presents an average improvement of 30\% with respect to previous work. Still, significant technological development is required to reach and be captured in the Alpha-Centauri system in less than a century. Therefore, a fly-through mission arguably remains the only option for a first exploratory mission to Alpha Centauri, but the enticing results obtained in this work provide perspective for future long-residence missions to our closest neighbouring star system.}, language = {en} } @inproceedings{SeefeldtBauerDachwaldetal.2015, author = {Seefeldt, Patric and Bauer, Waldemar and Dachwald, Bernd and Grundmann, Jan Thimo and Straubel, Marco and Sznajder, Maciej and T{\´o}th, Norbert and Zander, Martin E.}, title = {Large lightweight deployable structures for planetary defence: solar sail propulsion, solar concentrator payloads, large-scale photovoltaic power}, series = {4th IAA Planetary Defense Conference - PDC 2015, 13-17 April 2015, Frascati, Roma, Italy}, booktitle = {4th IAA Planetary Defense Conference - PDC 2015, 13-17 April 2015, Frascati, Roma, Italy}, pages = {24}, year = {2015}, language = {en} } @inproceedings{Dachwald2017, author = {Dachwald, Bernd}, title = {Radiation pressure force model for an ideal laser-enhanced solar sail}, series = {4th International Symposium on Solar Sailing}, booktitle = {4th International Symposium on Solar Sailing}, pages = {1 -- 5}, year = {2017}, abstract = {The concept of a laser-enhanced solar sail is introduced and the radiation pressure force model for an ideal laser-enhanced solar sail is derived. A laser-enhanced solar sail is a "traditional" solar sail that is, however, not solely propelled by solar radiation, but additionally by a laser beam that illuminates the sail. The additional laser radiation pressure increases the sail's propulsive force and can give, depending on the location of the laser source, more control authority over the direction of the solar sail's propulsive force vector. This way, laser-enhanced solar sails may augment already existing solar sail mission concepts and make novel mission concepts feasible.}, language = {en} } @article{PeloniCeriottiDachwald2016, author = {Peloni, Alessandro and Ceriotti, Matteo and Dachwald, Bernd}, title = {Solar-sail trajectory design for a multiple near-earth-asteroid rendezvous mission}, series = {Journal of Guidance, Control, and Dynamics}, volume = {39}, journal = {Journal of Guidance, Control, and Dynamics}, number = {12}, publisher = {AIAA}, address = {Reston, Va.}, issn = {0731-5090}, doi = {10.2514/1.G000470}, pages = {2712 -- 2724}, year = {2016}, abstract = {The scientific interest for near-Earth asteroids as well as the interest in potentially hazardous asteroids from the perspective of planetary defense led the space community to focus on near-Earth asteroid mission studies. A multiple near-Earth asteroid rendezvous mission with close-up observations of several objects can help to improve the characterization of these asteroids. This work explores the design of a solar-sail spacecraft for such a mission, focusing on the search of possible sequences of encounters and the trajectory optimization. This is done in two sequential steps: a sequence search by means of a simplified trajectory model and a set of heuristic rules based on astrodynamics, and a subsequent optimization phase. A shape-based approach for solar sailing has been developed and is used for the first phase. The effectiveness of the proposed approach is demonstrated through a fully optimized multiple near-Earth asteroid rendezvous mission. The results show that it is possible to visit five near-Earth asteroids within 10 years with near-term solar-sail technology.}, language = {en} } @inproceedings{Dachwald2004, author = {Dachwald, Bernd}, title = {Solar sail performance requirements for missions to the outer solar system and beyond}, series = {55th International Astronautical Congress 2004}, booktitle = {55th International Astronautical Congress 2004}, doi = {10.2514/6.IAC-04-S.P.11}, pages = {1 -- 9}, year = {2004}, abstract = {Solar sails enable missions to the outer solar system and beyond, although the solar radiation pressure decreases with the square of solar distance. For such missions, the solar sail may gain a large amount of energy by first making one or more close approaches to the sun. Within this paper, optimal trajectories for solar sail missions to the outer planets and into near interstellar space (200 AU) are presented. Thereby, it is shown that even near/medium-term solar sails with relatively moderate performance allow reasonable transfer times to the boundaries of the solar system.}, language = {en} } @incollection{DachwaldUlamecKowalskietal.2023, author = {Dachwald, Bernd and Ulamec, Stephan and Kowalski, Julia and Boxberg, Marc S. and Baader, Fabian and Biele, Jens and K{\"o}mle, Norbert}, title = {Ice melting probes}, series = {Handbook of Space Resources}, booktitle = {Handbook of Space Resources}, editor = {Badescu, Viorel and Zacny, Kris and Bar-Cohen, Yoseph}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-97912-6 (Print)}, doi = {10.1007/978-3-030-97913-3_29}, pages = {955 -- 996}, year = {2023}, abstract = {The exploration of icy environments in the solar system, such as the poles of Mars and the icy moons (a.k.a. ocean worlds), is a key aspect for understanding their astrobiological potential as well as for extraterrestrial resource inspection. On these worlds, ice melting probes are considered to be well suited for the robotic clean execution of such missions. In this chapter, we describe ice melting probes and their applications, the physics of ice melting and how the melting behavior can be modeled and simulated numerically, the challenges for ice melting, and the required key technologies to deal with those challenges. We also give an overview of existing ice melting probes and report some results and lessons learned from laboratory and field tests.}, language = {en} } @article{BaaderBoxbergChenetal.2023, author = {Baader, Fabian and Boxberg, Marc S. and Chen, Qian and F{\"o}rstner, Roger and Kowalski, Julia and Dachwald, Bernd}, title = {Field-test performance of an ice-melting probe in a terrestrial analogue environment}, series = {Icarus}, journal = {Icarus}, number = {409}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.icarus.2023.115852}, pages = {Artikel 115852}, year = {2023}, abstract = {Melting probes are a proven tool for the exploration of thick ice layers and clean sampling of subglacial water on Earth. Their compact size and ease of operation also make them a key technology for the future exploration of icy moons in our Solar System, most prominently Europa and Enceladus. For both mission planning and hardware engineering, metrics such as efficiency and expected performance in terms of achievable speed, power requirements, and necessary heating power have to be known. Theoretical studies aim at describing thermal losses on the one hand, while laboratory experiments and field tests allow an empirical investigation of the true performance on the other hand. To investigate the practical value of a performance model for the operational performance in extraterrestrial environments, we first contrast measured data from terrestrial field tests on temperate and polythermal glaciers with results from basic heat loss models and a melt trajectory model. For this purpose, we propose conventions for the determination of two different efficiencies that can be applied to both measured data and models. One definition of efficiency is related to the melting head only, while the other definition considers the melting probe as a whole. We also present methods to combine several sources of heat loss for probes with a circular cross-section, and to translate the geometry of probes with a non-circular cross-section to analyse them in the same way. The models were selected in a way that minimizes the need to make assumptions about unknown parameters of the probe or the ice environment. The results indicate that currently used models do not yet reliably reproduce the performance of a probe under realistic conditions. Melting velocities and efficiencies are constantly overestimated by 15 to 50 \% in the models, but qualitatively agree with the field test data. Hence, losses are observed, that are not yet covered and quantified by the available loss models. We find that the deviation increases with decreasing ice temperature. We suspect that this mismatch is mainly due to the too restrictive idealization of the probe model and the fact that the probe was not operated in an efficiency-optimized manner during the field tests. With respect to space mission engineering, we find that performance and efficiency models must be used with caution in unknown ice environments, as various ice parameters have a significant effect on the melting process. Some of these are difficult to estimate from afar.}, language = {en} } @misc{FeldmannFranckeEspeetal.2022, author = {Feldmann, Marco and Francke, Gero and Espe, Clemes and Chen, Qian and Baader, Fabian and Boxberg, Marc S. and Sustrate, Anna-Marie and Kowalski, Julia and Dachwald, Bernd}, title = {Performance data of an ice-melting probe from field tests in two different ice environments}, doi = {10.5281/zenodo.6094866}, year = {2022}, abstract = {This dataset was acquired at field tests of the steerable ice-melting probe "EnEx-IceMole" (Dachwald et al., 2014). A field test in summer 2014 was used to test the melting probe's system, before the probe was shipped to Antarctica, where, in international cooperation with the MIDGE project, the objective of a sampling mission in the southern hemisphere summer 2014/2015 was to return a clean englacial sample from the subglacial brine reservoir supplying the Blood Falls at Taylor Glacier (Badgeley et al., 2017, German et al., 2021). The standardized log-files generated by the IceMole during melting operation include more than 100 operational parameters, housekeeping information, and error states, which are reported to the base station in intervals of 4 s. Occasional packet loss in data transmission resulted in a sparse number of increased sampling intervals, which where compensated for by linear interpolation during post processing. The presented dataset is based on a subset of this data: The penetration distance is calculated based on the ice screw drive encoder signal, providing the rate of rotation, and the screw's thread pitch. The melting speed is calculated from the same data, assuming the rate of rotation to be constant over one sampling interval. The contact force is calculated from the longitudinal screw force, which es measured by strain gauges. The used heating power is calculated from binary states of all heating elements, which can only be either switched on or off. Temperatures are measured at each heating element and averaged for three zones (melting head, side-wall heaters and back-plate heaters).}, language = {en} } @article{ArtmannTrzewikAtes2002, author = {Artmann, Gerhard and Trzewik, J{\"u}rgen and Ates, M.}, title = {A novel method to quantify mechanical tension in cell monolayers. Trzewik, J{\"u}rgen; Ates, M., Artmann, Gerhard Michael}, series = {Biomedizinische Technik. 47 (2002), H. Suppl. 1. Pt. 1}, journal = {Biomedizinische Technik. 47 (2002), H. Suppl. 1. Pt. 1}, isbn = {0013-5585}, pages = {379 -- 381}, year = {2002}, language = {en} } @article{MaggakisKelemenBiselliArtmann2002, author = {Maggakis-Kelemen, Christina and Biselli, Manfred and Artmann, Gerhard}, title = {Determination of the elastic shear modulus of cultured human red blood cells}, series = {Biomedizinische Technik. 47 (2002), H. Suppl. 1 Pt. 1}, journal = {Biomedizinische Technik. 47 (2002), H. Suppl. 1 Pt. 1}, isbn = {0013-5585}, pages = {106 -- 109}, year = {2002}, language = {en} } @article{ArtmannZhouStacheBuettneretal.2002, author = {Artmann, Gerhard and Zhou-Stache, J. and Buettner, R. and Mittermayer, C. [u.a.]}, title = {Inhibition of TNF-alpha induced cell death in HUVEC and Jurkat cells by protocatechuic acid. Zhou-Stache, J.; Buettner, R.; Artmann, Gerhard Michael; Mittermayer, C.; Bosserhoff, A. K.}, series = {Medical and Biological Engineering and Computing. 40 (2002), H. 6}, journal = {Medical and Biological Engineering and Computing. 40 (2002), H. 6}, isbn = {0140-0118}, pages = {698 -- 703}, year = {2002}, language = {en} } @article{ArtmannTrzewikMallipattuetal.2001, author = {Artmann, Gerhard and Trzewik, J{\"u}rgen and Mallipattu, S. K. and Delano, F. A. [u.a.]}, title = {Evidence for a second valve system in Lymphatics: Endothelial Microvalves. Trzewik, J{\"u}rgen; Mallipattu, S. K.; Artmann, Gerhard Michael; Delano, F. A.; Schmid-Schonbein, G. W}, series = {The FASEB Journal. 15 (2001)}, journal = {The FASEB Journal. 15 (2001)}, isbn = {1530-6860}, pages = {1711 -- 1717}, year = {2001}, language = {en} } @article{ArtmannBaeumlerVoigtetal.2000, author = {Artmann, Gerhard and B{\"a}umler, H. and Voigt, A. and Mitl{\"o}hner, R. [u.a.]}, title = {Plastic behaviour of polyelectrolyte microcapsules derived from colloid templates. B{\"a}umler, H., Artmann, Gerhard Michael; Voigt, A., Mitl{\"o}hner, R., Neu, B., Kiesewetter, H.}, series = {Journal of Microencapsulation. 17 (2000), H. 5}, journal = {Journal of Microencapsulation. 17 (2000), H. 5}, isbn = {1464-5246}, pages = {651 -- 655}, year = {2000}, language = {en} } @article{ArtmannGorbatenkovaPanasenko2000, author = {Artmann, Gerhard and Gorbatenkova, E. A. and Panasenko, O. M.}, title = {Hypochlorous acid and human blood low density lipoproteins modified by hypochlorous acid increase erythrocyte adhesion to endothelial cells. Gorbatenkova, E. A.; Artmann, Gerhard Michael; Panasenko, O. M.}, series = {Membrane and cell biology. 13 (2000), H. 4}, journal = {Membrane and cell biology. 13 (2000), H. 4}, isbn = {1023-6597}, pages = {537 -- 546}, year = {2000}, language = {en} } @article{ArtmannKelemenChien2001, author = {Artmann, Gerhard and Kelemen, C. and Chien, S.}, title = {Temperature transition of human hemoglobin at body temperature: effects of calcium. Kelemen, C.; Chien, S.; Artmann, Gerhard Michael}, series = {Biophysical journal. 80 (2001), H. 6}, journal = {Biophysical journal. 80 (2001), H. 6}, isbn = {1542-0086}, pages = {2622 -- 2630}, year = {2001}, language = {en} } @article{ArtmannHueckHollwegetal.2000, author = {Artmann, Gerhard and Hueck, I. S. and Hollweg, H. G. and Schmid-Sch{\"o}nbein, G. W.}, title = {Chlorpromazine modulates the Morphological Macro- and Microstructure of Endothelial Cells. Hueck, I. S.; Hollweg, H. G.; Schmid-Sch{\"o}nbein, G. W.; Artmann, Gerhard Michael}, series = {American Journal of Physiology. Cell Physiology. 278 (2000), H. 5}, journal = {American Journal of Physiology. Cell Physiology. 278 (2000), H. 5}, isbn = {1522-1563}, pages = {873 -- 878}, year = {2000}, language = {en} } @article{ArtmannLiSeipeltetal.1999, author = {Artmann, Gerhard and Li, Anlan and Seipelt, H. and M{\"u}ller, C. [u.a.]}, title = {Effects of salicylic acid derivatives on red blood cell membranes. Li, Anlan; Seipelt, H.; M{\"u}ller, C.;Shi, Yong de; Artmann, Gerhard Michael}, series = {Pharmacology and Toxicology. 85 (1999)}, journal = {Pharmacology and Toxicology. 85 (1999)}, isbn = {0902-9938}, pages = {206 -- 211}, year = {1999}, language = {en} } @article{ArtmannHovavGoldfarbetal.1999, author = {Artmann, Gerhard and Hovav, T. and Goldfarb, A. and Yedgar, S. [u.a.]}, title = {Enhanced adherence of beta-thalassaemic erythrocytes to endothelial cells. Hovav, T., Goldfarb, A.; Artmann, Gerhard Michael, Yedgar, S.; Barstein, G.}, series = {British Journal of Haematology. 106 (1999), H. 1}, journal = {British Journal of Haematology. 106 (1999), H. 1}, isbn = {1365-2141}, pages = {178 -- 181}, year = {1999}, language = {en} } @article{ArtmannKelemenPorstetal.1998, author = {Artmann, Gerhard and Kelemen, Christina and Porst, Dariusz and B{\"u}ldt, G. [u.a.]}, title = {Temperature transitions of protein properties in human red blood cells. Artmann, Gerhard Michael, Kelemen, Christina; Porst, D.; B{\"u}ldt, G.; Chien, S.}, series = {Biophysical Journal. 75 (1998), H. 6}, journal = {Biophysical Journal. 75 (1998), H. 6}, isbn = {1542-0086}, pages = {3179 -- 3183}, year = {1998}, language = {en} } @article{ArtmannShiAgostietal.1998, author = {Artmann, Gerhard and Shi, Young de and Agosti, R. and Longhini, E.}, title = {A modified casson equation to characterize blood rheology for hypertension. Shi, Young de; Artmann, Gerhard Michael; Agosti, R.; Longhini, E.}, series = {Clinical Hemorheology Microcirculation. 19 (1998), H. 2}, journal = {Clinical Hemorheology Microcirculation. 19 (1998), H. 2}, isbn = {1386-0291}, pages = {115 -- 127}, year = {1998}, language = {en} } @article{LiShiLandsmannetal.1998, author = {Li, Anlan and Shi, Young de and Landsmann, B. and Schankowski-Bouvier, P. and Dikta, Gerhard and Bauer, U. and Artmann, Gerhard}, title = {Hemorheology and walking distance of Peripheral Arterial Occlusive Disease patients during treatment with Ginkgo-biloba extract}, series = {Acta Pharmacologica Sinica = ZHONGUO YAOLI XUEBAO. 19 (1998), H. 5}, journal = {Acta Pharmacologica Sinica = ZHONGUO YAOLI XUEBAO. 19 (1998), H. 5}, isbn = {1745-7254}, pages = {417 -- 421}, year = {1998}, language = {en} } @article{ArtmannSchikarsky1993, author = {Artmann, Gerhard and Schikarsky, C.}, title = {Ginkgo Biloba extract (EGb 761) protects red blood cells from oxidative damage. Artmann, Gerhard Michael; Schikarsky, C.}, series = {Clinical Hemorheology. 13 (1993), H. 4}, journal = {Clinical Hemorheology. 13 (1993), H. 4}, isbn = {0271-5198}, pages = {529 -- 539}, year = {1993}, language = {en} } @article{Artmann1986, author = {Artmann, Gerhard}, title = {A microscopic photometric method for measuring erythrocyte deformability. Artmann, Gerhard Michael}, series = {Clinical Hemorheology. 6 (1986)}, journal = {Clinical Hemorheology. 6 (1986)}, isbn = {0271-5198}, pages = {617 -- 627}, year = {1986}, language = {en} } @article{ArtmannSchmidSchoenbeinGrebeetal.1988, author = {Artmann, Gerhard and Schmid-Sch{\"o}nbein, H. and Grebe, R. and Teitel, P. [u.a.]}, title = {Restoration of Microsieve Filterability of Human Red Cells After Exposure to Hyperosmolarity and Lactazidosis: Effect of Vinpocetine. Schmid-Sch{\"o}nbein, H.; Grebe, R.; Teitel, P.; Artmann, Gerhard Michael, Eschweiler, H.; Schr{\"o}der, Susanne}, series = {Drug Development Research. 14 (1988), H. 3-4}, journal = {Drug Development Research. 14 (1988), H. 3-4}, isbn = {1098-2299}, pages = {205 -- 211}, year = {1988}, language = {en} } @article{ArtmannSchmidSchoenbeinSchroederetal.1988, author = {Artmann, Gerhard and Schmid-Sch{\"o}nbein, H. and Schr{\"o}der, Susanne and Grebe, R. [u.a.]}, title = {Influence of Moxaverine-HCL on Membrane Curvature and Microsieve Filterability of Red Cells after Exposure to Hyperosmolarity and Lactacidosis. Schmid-Sch{\"o}nbein, H.; Schr{\"o}der, Susanne; Grebe, R.; Artmann, Gerhard Michael, Eschweiler, H; Teitel, P.}, series = {Arzneimittelforschung. 38 (1988), H. 5}, journal = {Arzneimittelforschung. 38 (1988), H. 5}, isbn = {0004-4172}, pages = {710 -- 716}, year = {1988}, language = {en} } @article{ArtmannZang1990, author = {Artmann, Gerhard and Zang, Werner}, title = {Fully automatic measurement of rheologic parameters of red blood cells = Laborautomat zur Messung mechanischer Eigenschaften roter Blutzellen}, series = {Biomedizinische Technik = Biomedical engineering. 35 (1990), H. Suppl. 3}, journal = {Biomedizinische Technik = Biomedical engineering. 35 (1990), H. Suppl. 3}, isbn = {0013-5585}, pages = {94 -- 96}, year = {1990}, language = {en} } @article{ArtmannSungHornetal.1997, author = {Artmann, Gerhard and Sung, K.-L. Paul and Horn, Thomas and Whittemore, Darren [u.a.]}, title = {Micropipette aspiration of human erythrocytes induces echinocytes via membrane phospholipid translocation. Artmann, Gerhard Michael; Sung, K.-L. Paul; Horn, Thomas; Whittemore, Darren; Norwich, Gerald; Chien, Shu}, series = {Biophysical journal. 72 (1997), H. 3}, journal = {Biophysical journal. 72 (1997), H. 3}, isbn = {1542-0086}, pages = {1434 -- 1441}, year = {1997}, language = {en} } @article{ArtmannLiZiemeretal.1996, author = {Artmann, Gerhard and Li, Anlan and Ziemer, J. and Schneider, G. [u.a.]}, title = {A photometric method to analyze induced erythrocyte shape changes. Artmann, Gerhard Michael; Li, Anlan; Ziemer, J.; Schneider, G.; Sahm, U.: ; Ziemer, J.; Schneider, G.; Sahm, U.}, series = {Biorheology. 33 (1996), H. 3}, journal = {Biorheology. 33 (1996), H. 3}, isbn = {0006-355x}, pages = {251 -- 265}, year = {1996}, language = {en} } @article{Artmann1996, author = {Artmann, Gerhard}, title = {2nd International Conference on Medical Biorheology (ICMB). Shanghai, China, September 13-15, 1995. Shi, Young de, Artmann, Gerhard Michael, Meiselman, Herbert J.}, series = {Biorheology. 33 (1996), H. 6}, journal = {Biorheology. 33 (1996), H. 6}, isbn = {0006-355x}, pages = {505 -- 507}, year = {1996}, language = {en} } @article{Artmann1995, author = {Artmann, Gerhard}, title = {Microscopic photometric quantification of stiffness and relaxation time of red blood cells in a flow chamber. Artmann, Gerhard Michael}, series = {Biorheology. 32 (1995), H. 5}, journal = {Biorheology. 32 (1995), H. 5}, isbn = {0006-355x}, pages = {553 -- 570}, year = {1995}, language = {en} } @article{ArtmannLi1994, author = {Artmann, Gerhard and Li, Anlan}, title = {Dihydroergocryptine maintains erythrocyte fluidity in acidotic and hyperosmolar suspensions modelling hypoxic and ischemic microcirculation. Li, Anlan; Artmann, Gerhard Michael}, series = {Clinical Hemorheology. 15 (1994), H. 2}, journal = {Clinical Hemorheology. 15 (1994), H. 2}, isbn = {0271-5198}, pages = {133 -- 146}, year = {1994}, language = {en} } @article{ArtmannSchmidSchoenbein1987, author = {Artmann, Gerhard and Schmid-Sch{\"o}nbein, H.}, title = {The microscope-photometrical-monolayer-technique- a new principle for analyzing the distribution of rheological responses in pathological and experimentally modified red cell populations. Artmann, Gerhard Michael; Schmid-Sch{\"o}nbein, H.}, series = {Microcirculation, an update : proceedings of the Fourth World Congress for Microcirculation, Tokyo, Japan, July 26-30, 1987}, journal = {Microcirculation, an update : proceedings of the Fourth World Congress for Microcirculation, Tokyo, Japan, July 26-30, 1987}, publisher = {Excerpta Medica}, address = {Amsterdam [u.a.]}, isbn = {0444809511}, pages = {475 -- 477}, year = {1987}, language = {en} } @article{ArtmannTeitelSchmidSchoenbein1987, author = {Artmann, Gerhard and Teitel, P. and Schmid-Sch{\"o}nbein, H.}, title = {Variable rheologische Antwort der Erythrozyten auf den Einfluß von Xantinderivaten (Coffein): Experimentelle Differenzierung von "Responders" und "Nonresponders"}, series = {11. Jahrestagung der Gesellschaft f{\"u}r Mikrozirkulation}, journal = {11. Jahrestagung der Gesellschaft f{\"u}r Mikrozirkulation}, publisher = {Karger [u.a.]}, address = {Basel [u.a.]}, pages = {100 -- 105}, year = {1987}, language = {de} } @article{ArtmannGrebeHomrighausenetal.1988, author = {Artmann, Gerhard and Grebe, R. and Homrighausen, A. and Wolff, H. and [u.a.],}, title = {Response of normal and diabetic erythrocytes to membrane deformation by chemical and mechanical forces. Artmann, Gerhard Michael; Grebe, R.; Homrighausen, A.; Wolff, H.; Teitel, P.; Schmid-Sch{\"o}nbein, H.}, series = {12. Jahrestagung der Gesellschaft f{\"u}r Mikrozirkulation}, journal = {12. Jahrestagung der Gesellschaft f{\"u}r Mikrozirkulation}, publisher = {Karger [u.a.]}, address = {Basel [u.a.]}, pages = {196 -- 200}, year = {1988}, language = {en} } @article{ArtmannKellerHaasetal.1991, author = {Artmann, Gerhard and Keller, U. and Haas, J. and Amort, U. and Zang, Werner and Karschies, S.}, title = {Technik und ausgew{\"a}hlte Applikationen eines Membranbioassays roter Blutzellen}, series = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, volume = {36}, journal = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, number = {S1}, isbn = {0013-5585}, pages = {450 -- 451}, year = {1991}, language = {de} } @article{ArtmannMontanusTeitel1991, author = {Artmann, Gerhard and Montanus, M. and Teitel, P.}, title = {Die photometrische Kapillaraggregation- ein neues Verfahren zur Messung der Erythrozytenaggregation. Montanus, M.; Artmann, Gerhard Michael; Teitel, P.}, series = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, journal = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, isbn = {0013-5585}, pages = {213 -- 215}, year = {1991}, language = {de} } @article{ArtmannWitte1991, author = {Artmann, Gerhard and Witte, Ch.}, title = {Expertensystem f{\"u}r Personal Computer zur Strukturbestimmung des Circulus Arteriosus Willisii mittels transkranieller Dopplersonografie. Witte, Ch.; Artmann, Gerhard Michael}, series = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, journal = {Biomedizinische Technik = Biomedical engineering. 36 (1991)}, isbn = {0013-5585}, pages = {228 -- 230}, year = {1991}, language = {de} } @article{MaggakisKelemenBorkKayseretal.2003, author = {Maggakis-Kelemen, C. and Bork, M. and Kayser, Peter and Biselli, Manfred and Artmann, Gerhard}, title = {Biological and mechanical quality of red blood cells cultured from human umbilical cord blood stem cells}, series = {Medical and biological engineering and computing. 41 (2003), H. 3}, journal = {Medical and biological engineering and computing. 41 (2003), H. 3}, isbn = {0140-0118}, pages = {350 -- 356}, year = {2003}, language = {en} } @article{ArtmannHueckRossiteretal.2008, author = {Artmann, Gerhard and Hueck, Isgard S. and Rossiter, Katharine and Schmid-Sch{\"o}nbein, Geert W.}, title = {Fluid Shear Attenuates Endothelial Pseudopodia Formation into the Capillary Lumen / Hueck, Isgard S. ; Rossiter, Katharine ; Artman, Gerhard M. ; Schmid-Sch{\"o}nbein, Geert W.}, series = {Microcirculation. 15 (2008), H. 6}, journal = {Microcirculation. 15 (2008), H. 6}, isbn = {1549-8719}, pages = {531 -- 542}, year = {2008}, language = {en} } @book{Artmann2008, author = {Artmann, Gerhard}, title = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-75408-4}, year = {2008}, language = {en} } @article{KaulKoshkaryevArtmannetal.2008, author = {Kaul, D. K. and Koshkaryev, A. and Artmann, Gerhard and Barshtein, G. and Yedgar, S.}, title = {Additive effect of red blood cell rigidity and adherence to endothelial cells in inducing vascular resistance}, series = {American Journal of Physiology : Heart and Circulation Physiology . 295 (2008), H. 4}, volume = {295}, journal = {American Journal of Physiology : Heart and Circulation Physiology . 295 (2008), H. 4}, number = {4}, issn = {1522-1539}, pages = {H1788 -- H1793}, year = {2008}, language = {en} } @article{BeckerWallangArtmannetal.2008, author = {Becker, C. and Wallang, C. and Artmann, Gerhard and Jakse, G.}, title = {Mechanotransduction-bioreactor for tissue engineering of a ureter prosthesis}, series = {International Journal of Artificial Organs, The}, volume = {31}, journal = {International Journal of Artificial Organs, The}, number = {7}, issn = {0391-3988}, pages = {583 -- 583}, year = {2008}, language = {en} } @article{BorkKelemenBisellietal.2000, author = {Bork, M. and Kelemen, C. and Biselli, Manfred and Artmann, Gerhard}, title = {Biophysikalische Charakterisierung ex vivo kultivierter menschlicher Erythrozythen}, series = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, journal = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, isbn = {1862-278X}, pages = {471 -- 472}, year = {2000}, language = {de} } @article{ArtmannStacheKoenigsfeld2000, author = {Artmann, Gerhard and Stache, O. and K{\"o}nigsfeld, J.}, title = {Temperaturabh{\"a}ngigkeit der Pseudopodienbildung und R{\"u}ckbildung von Granulozyten / Stache, O. ; K{\"o}nigsfeld, J. ; Artmann, G. M.}, series = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, journal = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, isbn = {1862-278X}, pages = {450 -- 451}, year = {2000}, language = {de} } @article{ArtmannTrzewikSchmidSchoenbein2000, author = {Artmann, Gerhard and Trzewik, J. and Schmid-Sch{\"o}nbein, G. W.}, title = {Investigation on lymphatic endothelial microvalves / Trzewik, J. ; Artmann, G. M. ; Schmid-Sch{\"o}nbein, G. W.}, series = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, journal = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, isbn = {1862-278X}, pages = {521 -- 522}, year = {2000}, language = {en} } @article{ArtmannVogelZinketal.2000, author = {Artmann, Gerhard and Vogel, A. and Zink, S. and Stache, O.}, title = {Entwicklung eines automatisierten, computergesteuerten Permeabilit{\"a}tsanalysators zur Messung an Endothelzellen / Vogel, A. ; Zinke, S. ; Stache, O. ; K{\"o}nigsfeld, J. ; Artmann, G.}, series = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, journal = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, isbn = {1862-278X}, pages = {479 -- 480}, year = {2000}, language = {de} } @article{Artmann2000, author = {Artmann, Gerhard}, title = {Cellular engineering - a challenge for engineers? / Artmann, G. M.}, series = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, journal = {Biomedizinische Technik = Biomedical Engineering. 45 (2000), H. s1}, isbn = {1862-278X}, pages = {449}, year = {2000}, language = {en} } @article{ArtmannKelemenPorstetal.1998, author = {Artmann, Gerhard and Kelemen, C. and Porst, Dariusz and B{\"u}ldt, G.}, title = {Cellular engineering: Crash tests an menschlichen Erythrozyten geben Aufschluß {\"u}ber versteckte Materialeigenschaften zellul{\"a}rer Proteine / Artmann, G. M. ; Kelemen, Ch. ; Porst, D. ; B{\"u}ldt, G. ; Chien, Shu}, series = {Biomedizinische Technik / Biomedical Engineering. 43 (1998), H. s1}, journal = {Biomedizinische Technik / Biomedical Engineering. 43 (1998), H. s1}, isbn = {1862-278}, pages = {446 -- 447}, year = {1998}, language = {en} } @article{EijckDemmelArtmannetal.2011, author = {Eijck, Lambert van and Demmel, Franz and Artmann, Gerhard and Stadtler, Andreas Maximilian}, title = {Macromolecular dynamics in red blood cells investigated using neutron spectroscopy}, series = {Journal of the Royal Society Interface}, volume = {8}, journal = {Journal of the Royal Society Interface}, number = {57}, publisher = {The Royal Society}, address = {London}, isbn = {1742-5689}, pages = {590 -- 600}, year = {2011}, language = {en} } @book{Artmann2011, author = {Artmann, Gerhard}, title = {Stem cell engineering : principles and applications / Gerhard M. Artmann ... eds.}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-11864-7}, pages = {XLI, 541 S. : Ill., graph. Darst.}, year = {2011}, language = {en} } @article{ArtmannZang1990, author = {Artmann, Gerhard and Zang, Werner}, title = {Vollautomatische Messung rheologischer Parameter roter Blutzellen}, series = {Biomedizinische Technik / Biomedical Engineering}, volume = {35}, journal = {Biomedizinische Technik / Biomedical Engineering}, number = {S3}, issn = {0013-5585}, pages = {94 -- 96}, year = {1990}, language = {de} } @article{StadlerGarveyEmbsetal.2014, author = {Stadler, Alexander Maximilian and Garvey, Christopher J. and Embs, Jan Peter and Koza, Michael Marek and Unruh, Tobias and Artmann, Gerhard and Zaccai, Guiseppe}, title = {Picosecond dynamics in haemoglobin from different species: A quasielastic neutron scattering study}, series = {Biochimica et biophysica acta (BBA): General Subjects}, volume = {1840}, journal = {Biochimica et biophysica acta (BBA): General Subjects}, number = {10}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-8006 (E-Journal); 0304-4165 (Print)}, doi = {10.1016/j.bbagen.2014.06.007}, pages = {2989 -- 2999}, year = {2014}, language = {en} } @phdthesis{Artmann1988, author = {Artmann, Gerhard}, title = {Monolayer-Photometrie zur Quantifizierung der Form und induzierter Formver{\"a}nderungen menschlicher Erythrozyten}, pages = {143 S. : Ill., graph. Darst.}, year = {1988}, language = {de} } @phdthesis{Artmann1999, author = {Artmann, Gerhard}, title = {Methodische und experimentelle Beitr{\"a}ge zur Analyse der Ruheform, der Verformung und der Integrit{\"a}t humaner Erythrozyten}, pages = {144 S. : Ill., graph. Darst.}, year = {1999}, language = {de} } @misc{ArtmannLinderBayeretal.2017, author = {Artmann, Gerhard and Linder, Peter and Bayer, Robin and Gossmann, Matthias}, title = {Celldrum electrode arrangement for measuring mechanical stress [Patent of invention]}, publisher = {WIPO}, address = {Geneva}, pages = {18 Seiten}, year = {2017}, abstract = {The invention pertains to a CellDrum electrode arrangement for measuring mechanical stress, comprising a mechanical holder (1 ) and a non-conductive membrane (4), whereby the membrane (4) is at least partially fixed at its circumference to the mechanical holder (1), keeping it in place when the membrane (4) may bend due to forces acting on the membrane (4), the mechanical holder (1) and the membrane (4) forming a container, whereby the membrane (1) within the container comprises an cell- membrane compound layer or biological material (3) adhered to the deformable membrane 4 which in response to stimulation by an agent may exert mechanical stress to the membrane (4) such that the membrane bending stage changes whereby the container may be filled with an electrolyte, whereby an electric contact (2) is arranged allowing to contact said electrolyte when filled into to the container, whereby within a predefined geometry to the fixing of the membrane (4) an electrode (7) is arranged, whereby the electrode (7) is electrically insulated with respect to the electric contact (2) as well as said electrolyte, whereby mechanical stress due to an agent may be measured as a change in capacitance.}, language = {en} } @incollection{AzatKerimkulovaMansurovetal.2020, author = {Azat, Seitkhan and Kerimkulova, Almagul R. and Mansurov, Zulkhair A. and Adekenov, Sergazy and Artmann, Gerhard}, title = {The Use of Fusicoccin as Anticancer Compound}, series = {Carbon Nanomaterials in Biomedicine and the Environment}, booktitle = {Carbon Nanomaterials in Biomedicine and the Environment}, publisher = {Jenny Stanford Publishing}, address = {New York}, isbn = {978-0-429-42864-7}, doi = {10.1201/9780429428647-8}, pages = {149 -- 172}, year = {2020}, abstract = {The problem of creation and use of sorption materials is of current interest for the practice of the modern medicine and agriculture. Practical importance is production of a biostimulant using a carbon sorbent for a significant increase in productivity, which is very relevant for the regions of Kazakhstan. It is known that a plant phytohormone—fusicoccin—in nanogram concentrations transforms cancer cells to the state of apoptosis. In this regard, there is a scientific practical interest in the development of a highly efficient method for producing fusicoccin from extract of germinated wheat seeds. According to the results of computer modeling, cleaning composite components of fusicoccin using microporous carbon adsorbents not suitable as the size of the molecule of fusicoccin more than micropores and the optimum pore size for purification of constituents of fusicoccin was determined by computer simulation.}, language = {en} } @techreport{Artmann2011, author = {Artmann, Gerhard}, title = {HPBioforce: Integrierte und automatisierte Screening Plattform eines 96-Well-Hochdurchsatz-Testsystems zur funktionellen Kraftmessung an einige um dicken Zell- und Gewebeschichten f{\"u}r die Arzneimittelforschung : gemeinsamer Abschlussbericht der FH Aachen, Hitec Zang GmbH, IKFE Mainz, IKFE Berlin und der Dr. Gerhard Schmidt GmbH zum InnoNet-Projekt ... ; Programm "F{\"o}rderung von innovativen Netzwerken" (InnoNet) des Bundesministerium f{\"u}r Wirtschaft und Technologie (BMWi) ; Laufzeit: 01.05.2007 bis 31.12.2010}, publisher = {Technische Informationsbibliothek u. Universit{\"a}tsbibliothek}, address = {Aachen [u.a.]}, doi = {10.2314/GBV:68757076X}, year = {2011}, language = {de} } @techreport{Artmann2011, author = {Artmann, Gerhard}, title = {FhprofUnd EasyBioforce Abschlussbericht : Miniaturisierte, integrierte und automatisierte Screening Plattform eines 36-Well-Hochdurchsatz-Testsystems zur funktionellen Kraftmessung an Zell- und Gewebeschichten f{\"u}r die Arzneimittelforschung : Laufzeit des Vorhabens: 01.03.2007 - 31.12.2010}, publisher = {Technische Informationsbibliothek u. Universit{\"a}tsbibliothek}, address = {Aachen}, doi = {10.2314/GBV:782964621}, year = {2011}, language = {de} } @techreport{Artmann2004, author = {Artmann, Gerhard}, title = {Escherichia Coli Infektion und Zellsch{\"a}digung - Wie perfekt wirken Antibiotika? : Abschlussbericht zum Projekt 1703701}, publisher = {Technische Informationsbibliothek u. Universit{\"a}tsbibliothek}, address = {J{\"u}lich}, doi = {10.2314/GBV:482527137}, year = {2004}, language = {de} } @techreport{Artmann2011, author = {Artmann, Gerhard}, title = {Plant mutant scanner : Hochdurchsatzscanner zur Charakterisierung von Pflanzenmutanten. Abschlussbericht ; FHprofUnd ; PhytoScan ; Laufzeit des Vorhabens: 01.07.2008 - 30.06.2011}, publisher = {Technische Informationsbibliothek u. Universit{\"a}tsbibliothek}, address = {Aachen}, doi = {10.2314/GBV:747569150}, year = {2011}, language = {de} } @techreport{ArtmannBaeumler2002, author = {Artmann, Gerhard and B{\"a}umler, H.}, title = {Pharmamikrocontainer mit designgesteuerter Permeabilit{\"a}t als Transporter f{\"u}r ausgew{\"a}hlte Pharmaka. Ein Gemeinschaftsprojekt im Forschungsschwerpunkt "Celluar Engineering" [Laufzeit: 01.09.2000 - 28.02.2002]}, publisher = {FH Aachen}, address = {J{\"u}lich}, year = {2002}, language = {de} } @article{StaatBallmann1988, author = {Staat, Manfred and Ballmann, J.}, title = {Computation of impacts on elastic solids by methods of bicharacteristics}, series = {Computational Mechanics '88 : theory and applications ; proceedings of the International Conference on Computational Engineering Science April 10-14, 1988, Atlanta, GA, USA ; vol. 2}, journal = {Computational Mechanics '88 : theory and applications ; proceedings of the International Conference on Computational Engineering Science April 10-14, 1988, Atlanta, GA, USA ; vol. 2}, pages = {1719 -- 1722}, year = {1988}, abstract = {Shock waves, explosions, impacts or cavitation bubble collapses may generate stress waves in solids causing cracks or unexpected dammage due to focussing, physical nonlinearity or interaction with existing cracks. There is a growing interest in wave propagation, which poses many novel problems to experimentalists and theorists.}, subject = {Bicharakteristikenverfahren}, language = {en} } @inproceedings{StaatSzelinskiHeitzer2001, author = {Staat, Manfred and Szelinski, E. and Heitzer, Michael}, title = {Kollapsanalyse von l{\"a}ngsfehlerbehafteten Rohren und Beh{\"a}ltern}, year = {2001}, abstract = {Es werden verbesserte Kollapsanalysen von dickwandigen, mit axialen Oberfl{\"a}chenfehlern behafteten Rohren und Beh{\"a}ltern vorgeschlagen.}, subject = {Druckbeh{\"a}lter}, language = {de} } @inproceedings{StaatTranPham2008, author = {Staat, Manfred and Tran, Thanh Ngoc and Pham, Phu Tinh}, title = {Limit and shakedown reliability analysis by nonlinear programming}, year = {2008}, abstract = {7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs.}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{TranPhamStaat2008, author = {Tran, Thanh Ngoc and Pham, Phu Tinh and Staat, Manfred}, title = {Reliability analysis of shells based on direct plasticity methods}, year = {2008}, abstract = {Abstracts der CD-Rom Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) 30.06. - 04.07.2008 Venedig, Italien. 2 Seiten Zusammenfassung der Autoren mit graph. Darst. und Literaturverzeichnis}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{HeitzerStaat2000, author = {Heitzer, M. and Staat, Manfred}, title = {Direct FEM approach to design-by-analysis of pressurized components}, year = {2000}, abstract = {Abstracts of the ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main. Achema 2000 : special edition / Linde. [Ed.: Linde AG. Red.: Volker R. Leski]. - Wiesbaden : Linde AG, 2000. - 56 p. : Ill., . - pp: 79 - 81}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{StaatHeitzerHicken1998, author = {Staat, Manfred and Heitzer, M. and Hicken, E. F.}, title = {LISA, ein europ{\"a}isches Projekt zur direkten Berechnung der Tragf{\"a}higkeit duktiler Strukturen}, year = {1998}, abstract = {Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der Plastizit{\"a}t, die neben ausreichender Verformbarkeit keine einschr{\"a}nkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle f{\"u}r Details der Lastgeschichte und des Stoffverhaltens. Anders als die klassische Behandlung nichtlinearer Probleme der Strukturmechanik f{\"u}hrt die Methode auf Optimierungsprobleme. Diese sind bei realistischen FEM-Modellen sehr groß. Das hat die industrielle Anwendung der Traglast- und Einspielanalysen stark verz{\"o}gert. Diese Situation wird durch das Brite-EuRam Projekt LISA grundlegend ge{\"a}ndert. Die Autoren m{\"o}chten der Europ{\"a}ischen Kommission an dieser Stelle f{\"u}r die F{\"o}rderung ausdr{\"u}cklich danken. In LISA entsteht auf der Basis des industriellen FEM-Programms PERMAS ein Verfahren zur direkten Berechnung der Tragf{\"a}higkeit duktiler Strukturen. Damit kann der Betriebsbereich von Komponenten und Bauwerken auf den plastischen Bereich erweitert werden, ohne den Aufwand gegen{\"u}ber elastischen Analysen wesentlich zu erh{\"o}hen. Die beachtlichen Rechenzeitgewinne erlauben Parameterstudien und die Berechnung von Interaktionsdiagrammen, die einen schnellen {\"U}berblick {\"u}ber m{\"o}gliche Betriebsbereiche vermitteln. Es zeigt sich, daß abh{\"a}ngig von der Komponente und ihren Belastungen teilweise entscheidende Sicherheitsgewinne zur Erweiterung der Betriebsbereiche erzielt werden k{\"o}nnen. Das Vorgehen erfordert vom Anwender oft ein gewisses Umdenken. Es werden keine Spannungen berechnet, um damit Sicherheit und Lebensdauer zu interpretieren. Statt dessen berechnet man direkt die gesuchte Sicherheit. Der Post-Prozessor wird nur noch zur Modell- und Rechenkontrolle ben{\"o}tigt. Das Vorgehen ist {\"a}nhlich der Stabilit{\"a}tsanalyse (Knicken, Beulen). Durch namhafte industrielle Projektpartner werden Validierung und die Anwendbarkeit auf eine breite Palette technischer Probleme garantiert. Die ebenfalls in LISA geplante Zuverl{\"a}ssigkeitsanalyse ist erst auf der Basis direkter Verfahren effektiv m{\"o}glich. Ohne Traglast- und Einspielanalyse ist plastische Strukturoptimierung auch heute kaum durchf{\"u}hrbar.}, subject = {Finite-Elemente-Methode}, language = {de} } @inproceedings{StaatHeitzer1997, author = {Staat, Manfred and Heitzer, Michael}, title = {Direkte FEM-Berechnung der Tragf{\"a}higkeit hochbeanspruchter passiver Komponenten}, year = {1997}, abstract = {Genaue Kenntnis der Spannungen und Verformungen in passiven Komponenten gewinnt man mit detailierten inelastischen FEM Analysen. Die lokale Beanspruchung l{\"a}ßt sich aber nicht direkt mit einer Beanspruchbarkeit im strukturmechanischen Sinne vergleichen. Konzentriert man sich auf die Frage nach der Tragf{\"a}higkeit, dann vereinfacht sich die Analyse. Im Rahmen der Plastizit{\"a}tstheorie berechnen Traglast- und Einspielanalyse die tragbaren Lasten direkt und exakt. In diesem Beitrag wird eine Implementierung der Traglast- und Einspiels{\"a}tze in ein allgemeines FEM Programm vorgestellt, mit der die Tragf{\"a}higkeit passiver Komponenten direkt berechnet wird. Die benutzten Konzepte werden in Bezug auf die {\"u}bliche Strukturanalyse erl{\"a}utert. Beispiele mit lokal hoher Beanspruchung verdeutlichen die Anwendung der FEM basierten Traglast- und Einspielanalysen. Die berechneten Interaktionsdiagramme geben einen guten {\"U}berblick {\"u}ber die m{\"o}glichen Betriebsbereiche passiver Komponenten. Die Traglastanalyse bietet auch einen strukturmechanischen Zugang zur Kollapslast rißbehafteter Komponenten aus hochz{\"a}hem Material.}, subject = {Finite-Elemente-Methode}, language = {de} } @inproceedings{StaatHeitzer1997, author = {Staat, Manfred and Heitzer, Michael}, title = {Limit and shakedown analysis for plastic design}, year = {1997}, abstract = {Limit and shakedown theorems are exact theories of classical plasticity for the direct computation of safety factors or of the load carrying capacity under constant and varying loads. Simple versions of limit and shakedown analysis are the basis of all design codes for pressure vessels and pipings. Using Finite Element Methods more realistic modeling can be used for a more rational design. The methods can be extended to yield optimum plastic design. In this paper we present a first implementation in FE of limit and shakedown analyses for perfectly plastic material. Limit and shakedown analyses are done of a pipe-junction and a interaction diagram is calculated. The results are in good correspondence with the analytic solution we give in the appendix.}, subject = {Einspielen }, language = {en} } @inproceedings{LangWirtzHeitzeretal.1999, author = {Lang, H. and Wirtz, K. and Heitzer, Michael and Staat, Manfred and Oettel, R.}, title = {Zyklische Einspielversuche zur Verifikation von Shakedown-Analysen mittels FEM}, year = {1999}, abstract = {Im Rahmen von Erm{\"u}dungsanalysen ist nachzuweisen, daß die thermisch bedingten fortschreitenden Deformationen begrenzt bleiben. Hierzu ist die Abgrenzung des Shakedown-Bereiches (Einspielen) vom Ratchetting-Bereich (fortschreitende Deformation) von Interesse. Im Rahmen eines EU-gef{\"o}rderten Forschungsvorhabens wurden Experimente mit einem 4-Stab-Modell durchgef{\"u}hrt. Das Experiment bestand aus einem wassergek{\"u}hlten inneren Rohr und drei isolierten und beheizbaren {\"a}ußeren Probest{\"a}ben. Das System wurde durch alternierende Axialkr{\"a}fte, denen alternierende Temperaturen an den {\"a}ußeren St{\"a}ben {\"u}berlagert wurden, belastet. Die Versuchsparameter wurden teilweise nach vorausgegangenen Einspielanalysen gew{\"a}hlt. W{\"a}hrend der Versuchsdurchf{\"u}hrung wurden Temperaturen und Dehnungen zeitabh{\"a}ngig gemessen. Begleitend und nachfolgend zur Versuchsdurchf{\"u}hrung wurden die Belastungen und die daraus resultierenden Beanspruchungen nachvollzogen. Bei dieser inkrementellen elasto-plastischen Analyse mit dem Programm ANSYS wurden unterschiedliche Werkstoffmodelle angesetzt. Die Ergebnisse dieser Simulationsberechnung dienen dazu, die Shakedown-Analysen mittels FE-Methode zu verifizieren.}, subject = {Einspielen }, language = {de} } @inproceedings{StaatHeitzerHicken1999, author = {Staat, Manfred and Heitzer, Michael and Hicken, E. F.}, title = {LISA - ein europ{\"a}isches Projekt zur FEM-basierten Traglast- und Einspielanalyse}, year = {1999}, abstract = {Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der Plastizit{\"a}t, die neben ausreichender Verformbarkeit keine einschr{\"a}nkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle f{\"u}r Details der Lastgeschichte und des Stoffverhaltens. Anders als die klassische Behandlung nichtlinearer Probleme der Strukturmechanik f{\"u}hrt die Methode auf Optimierungsprobleme. Diese sind bei realistischen FEM-Modellen sehr groß. Das hat die industrielle Anwendung der Traglast- und Einspielanalysen stark verz{\"o}gert. Diese Situation wird durch das Brite-EuRam Projekt LISA grundlegend ge{\"a}ndert. In LISA entsteht auf der Basis des industriellen FEM-Programms PERMAS ein Verfahren zur direkten Berechnung der Tragf{\"a}higkeit duktiler Strukturen. Damit kann der Betriebsbereich von Komponenten und Bauwerken auf den plastischen Bereich erweitert werden, ohne den Aufwand gegen{\"u}ber elastischen Analysen wesentlich zu erh{\"o}hen. Die beachtlichen Rechenzeitgewinne erlauben Parameterstudien und die Berechnung von Interaktionsdiagrammen, die einen schnellen {\"U}berblick {\"u}ber m{\"o}gliche Betriebsbereiche vermitteln. Es zeigt sich, daß abh{\"a}ngig von der Komponente und ihren Belastungen teilweise entscheidende Sicherheitsgewinne zur Erweiterung der Betriebsbereiche erzielt werden k{\"o}nnen. Das Vorgehen erfordert vom Anwender oft ein gewisses Umdenken. Es werden keine Spannungen berechnet, um damit Sicherheit und Lebensdauer zu interpretieren. Statt dessen berechnet man direkt die gesuchte Sicherheit. Der Post-Prozessor wird nur noch zur Modell- und Rechenkontrolle ben{\"o}tigt. Das Vorgehen ist {\"a}hnlich der Stabilit{\"a}tsanalyse (Knicken, Beulen). Durch namhafte industrielle Projektpartner werden Validierung und die Anwendbarkeit auf eine breite Palette technischer Probleme garantiert. Die ebenfalls in LISA entwickelten Zuverl{\"a}ssigkeitsanalysen sind nichlinear erst auf der Basis direkter Verfahren effektiv m{\"o}glich. Ohne Traglast- und Einspielanalyse ist plastische Strukturoptimierung auch heute kaum durchf{\"u}hrbar. Auf die vorgesehenen Erweiterungen der Werkstoffmodellierung f{\"u}r nichtlineare Verfestigung und f{\"u}r Sch{\"a}digung konnte hier nicht eingegangen werden. Es herrscht ein deutlicher Mangel an Experimenten zum Nachweis der Grenzen zwischen elastischem Einspielen und dem Versagen durch LCF oder durch Ratchetting.}, subject = {Einspielen }, language = {de} } @inproceedings{StaatHeitzerReindersetal.2001, author = {Staat, Manfred and Heitzer, Michael and Reinders, H. and Schubert, F.}, title = {Einspielen und Ratchetting bei Zug- und Torsionsbelastung: Analyse und Experimente}, year = {2001}, abstract = {Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der klassischen Plastizit{\"a}tstheorie, die neben ausreichender Verformbarkeit keine einschr{\"a}nkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle f{\"u}r Details der Lastgeschichte und des Stoffverhaltens. Eine FEM-basierte Traglast- und Einspielanalyse f{\"u}r ideal plastisches Material wurde auf ein kinematisch verfestigendes Materialgesetz erweitert und in das Finite Element Programm PERMAS implementiert. In einem einfachen Zug-Torsionsexperiment wurde eine Hohlprobe mit konstanter Torsion und zyklischer Zugbelastung beansprucht, um die neue Implementierung zu verifizieren. Es konnte gezeigt werden, dass die Einspielanalyse gut mit den experimentellen Ergebnissen {\"u}bereinstimmt. Bei Verfestigung lassen sich wesentlich gr{\"o}ßere Sicherheiten nachweisen. Dieses Potential bedarf weiterer experimenteller Absicherung. Parallel dazu ist die Eisnpieltheorie auf fortschrittliche Verfestigungsans{\"a}tze zu erweitern.}, subject = {Zug-Druck-Beanspruchung}, language = {de} } @inproceedings{BallmannRaatschenStaat1985, author = {Ballmann, J. and Raatschen, Hans-J{\"u}rgen and Staat, Manfred}, title = {High stress intensities in focussing zones of waves}, doi = {10.1016/B978-0-444-42520-1.50015-3}, year = {1985}, abstract = {The propagation of mechanical waves in plates of isotropic elastic material is investigated. After a short introduction to the understanding of focussing of stress waves in a plate with a curved boundary the method of characteristics is applied to a plate of hyperelastic material. Using this method the propagation of acceleration waves is discussed. Based on this a numerical difference scheme is developed for solving initial-boundary-value problems and applied to two examples: propagation of a point disturbance in a homogeneously finitely strained non-linear elastic plate and geometrical focussing in al linear elastic plate.}, subject = {Technische Mechanik}, language = {en} } @inproceedings{TranNovacekTolbaetal.2011, author = {Tran, Thanh Ngoc and Novacek, V. and Tolba, R. and Klinge, U. and Turquier, F. and Staat, Manfred}, title = {Experimental and Computational approach to study colorectal anastomosis. ISB2011, Proceedings of the XXIII Congress of the International Society of Biomechanics, Brussels, Belgium, July 3-7, 2011}, year = {2011}, abstract = {Summary: This paper presents a methodology to study and understand the mechanics of stapled anastomotic behaviors by combining empirical experimentation and finite element analysis. Performance of stapled anastomosis is studied in terms of leakage and numerical results which are compared to in vitro experiments performed on fresh porcine tissue. Results suggest that leaks occur between the tissue and staple legs penetrating through the tissue.}, subject = {Anastomose}, language = {en} } @article{LeversStaatLaack2011, author = {Levers, A. and Staat, Manfred and Laack, Walter van}, title = {Analyse der Langzeitwirkung der MBST® KernspinResonanzTherapie bei Gonarthrose}, year = {2011}, abstract = {Originalausgabe: Orthop{\"a}dische Praxis Jg. 47. 2011 H. 11; S. 536-543. Mit freundlicher Genehmigung des Verlags Zusammenfassung: Auf der Basis von Patientenabfragen mittels Fragebogen zum Schmerzempfinden und zur Einschr{\"a}nkung bei Aktivit{\"a}ten des allt{\"a}glichen Lebens wird die Langzeitwirkung der MBST® KernspinResonanz-Therapie bei Gonarthrose untersucht. An der Studie nahmen 39 Patienten teil, bei denen die Therapie bis zu vier Jahre zur{\"u}ckliegt. Neben einer Gesamtbetrachtung wird der Erfolg auch in Abh{\"a}ngigkeit von Alter, Geschlecht und sportlicher Aktivit{\"a}t analysiert. Insgesamt weist die Studie auf eine anhaltende Verbesserung des Gesundheitszustands mit zum Teil deutlicher Schmerzlinderung auch noch nach vier Jahren hin, jedoch mit einer leichten Schmerzzunahme gegen Ende des Untersuchungszeitraums von vier Jahren. Eine tendenziell positivere Wirkung bei Frauen, {\"a}lteren Menschen oder auch sportlich nicht-aktiven Patienten l{\"a}sst auf eine m{\"o}gliche Beeinflussung des Erfolgs der Therapie durch ({\"U}ber-)Belastung im Alltag schließen. Ein zus{\"a}tzlich positiver Effekt der Therapie auf die Knochendichte ist ebenfalls denkbar, dies bleibt jedoch offen.}, subject = {Kniegelenkarthrose}, language = {de} } @article{GorissenStaatLaack2012, author = {Gorissen, P. and Staat, Manfred and Laack, Walter van}, title = {Experimentelle Kraftmessungen als Beitrag zur Wirksamkeitsbeurteilung von Schienbeinschonern im Fußballsport}, series = {OUP Zeitschrift f{\"u}r die orthop{\"a}dische und unfallchirurgische Praxis}, volume = {1}, journal = {OUP Zeitschrift f{\"u}r die orthop{\"a}dische und unfallchirurgische Praxis}, number = {1}, publisher = {Deutscher {\"A}rzte-Verlag}, address = {K{\"o}ln}, issn = {2193-5785}, doi = {10.3238/oup.2012.0010-0015}, pages = {10 -- 15}, year = {2012}, abstract = {Diese Studie besch{\"a}ftigte sich mit der D{\"a}mpfungswirkung von Schienbeinschonern, wie sie beim Fußball zum Einsatz kommen. Sie wurde mit Hilfe eines Pendelhammers durchgef{\"u}hrt, der verschiedene Aufschlagkr{\"a}fte auf die Schoner erm{\"o}glichte. Dabei wurde deutlich, dass Schienbeinschoner die beste Wirkung bei Maximalkr{\"a}ften unterhalb von 5kN erreichen k{\"o}nnen, dass bei gr{\"o}ßerer Belastung allerdings Verbesserungsbedarf besteht. Hierf{\"u}r konnte, u.a. durch den Einsatz neuer Materialien, ein guter Ansatzpunkt im „ad{\"a}quaten Zusammenspiel von Schale und Polsterung" der Schoner gefunden werden. Die Untersuchung hat weiterhin gezeigt, dass zumindest teilweise eine deutliche Verbesserung der D{\"a}mpfungswirkung der Schienbeinschoner in den letzten Jahren erreicht werden konnte.}, subject = {Fußball}, language = {de} } @inproceedings{BurgazziFioriniDeMagistrisetal.1998, author = {Burgazzi, L. and Fiorini, F. and De Magistris, W. (u.a.) and Lensa, W. von and Staat, Manfred and Altes, J.}, title = {Reliability Assessment of Passive Safety Systems}, series = {Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif.}, booktitle = {Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif.}, publisher = {American Society of Mechanical Engineers}, address = {New York}, year = {1998}, language = {en} } @article{StaatFioriniLensaetal.1997, author = {Staat, Manfred and Fiorini, G. L. and Lensa, W. von and Burgazzi, L.}, title = {Reliability Methods for Passive Safety Functions}, series = {Proceedings of the SMiRT 14 Post Conference Seminar No 18 on Passive Safety Features in Nuclear Installations}, journal = {Proceedings of the SMiRT 14 Post Conference Seminar No 18 on Passive Safety Features in Nuclear Installations}, address = {Pisa}, year = {1997}, language = {en} } @article{StaatHeitzer1997, author = {Staat, Manfred and Heitzer, M.}, title = {Limit and Shakedown Analysis for Plastic Safety of Complex Structures}, series = {Transactions of the 14th International Conference on Structural Dynamics in Reactor Technology (SMiRT-14) / Livolant, M. [ed]}, journal = {Transactions of the 14th International Conference on Structural Dynamics in Reactor Technology (SMiRT-14) / Livolant, M. [ed]}, address = {Lyon}, pages = {33 -- 40}, year = {1997}, language = {en} } @article{StaatHeitzer1997, author = {Staat, Manfred and Heitzer, M.}, title = {Limit and Shakedown Analysis Using a General Purpose Finite Element Code}, series = {Proceedings of NAFEMS World Congress '97 on Design, Simulation \& Optimisation : reliability \& applicability of computational methods ; Stuttgart, Germany, 9 - 11 April 1997}, journal = {Proceedings of NAFEMS World Congress '97 on Design, Simulation \& Optimisation : reliability \& applicability of computational methods ; Stuttgart, Germany, 9 - 11 April 1997}, publisher = {NAFEMS}, address = {Glasgow}, isbn = {1-87437-620-4}, pages = {522 -- 533}, year = {1997}, language = {en} } @article{Staat1996, author = {Staat, Manfred}, title = {Problems and Chances for Probabilistic Fracture Mechanics in the Analysis of Steel Pressure Boundary Reliability}, series = {Technical feasibility and reliability of passive safety systems for nuclear power plants. Proceedings of an Advisory Group Meeting held in J{\"u}lich, 21-24 November 1994}, journal = {Technical feasibility and reliability of passive safety systems for nuclear power plants. Proceedings of an Advisory Group Meeting held in J{\"u}lich, 21-24 November 1994}, address = {Vienna}, pages = {43 -- 55}, year = {1996}, language = {en} } @article{Staat1993, author = {Staat, Manfred}, title = {Sensitivity of and Influences on the Reliability of an HTR-Module Primary Circuit Pressure Boundary}, series = {Transactions of the 12th International Conference on Structural Mechanics in Reactor Technology (SMiRT-12) / Kussmaul, K. [ed]}, journal = {Transactions of the 12th International Conference on Structural Mechanics in Reactor Technology (SMiRT-12) / Kussmaul, K. [ed]}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0-444-81515-5}, pages = {147 -- 152}, year = {1993}, language = {en} } @article{Staat1993, author = {Staat, Manfred}, title = {Reliability of the Primary Circuit Pressure Boundary of an HTR-Module under Accident Conditions}, series = {Safety and reliability assessment : an integral approach ; ESREL'93 ; proceedings of the European Safety and Reliability Conference, Munich, Germany, May 10th - 12th 1993 / Kafka, P. [ed]}, journal = {Safety and reliability assessment : an integral approach ; ESREL'93 ; proceedings of the European Safety and Reliability Conference, Munich, Germany, May 10th - 12th 1993 / Kafka, P. [ed]}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0-444-81561-9}, pages = {331 -- 342}, year = {1993}, language = {en} } @article{Staat1992, author = {Staat, Manfred}, title = {Probabilistische Bewertung des bruchmechanischen Verhaltens der Prim{\"a}rkreisdruckumschließung eines HTR-Moduls}, year = {1992}, language = {de} } @article{Staat1991, author = {Staat, Manfred}, title = {Versagenswahrscheinlichkeit der Prim{\"a}rkreisdruckumschließung eines HTR-Moduls zur Prozeßw{\"a}rmegewinnung unter St{\"o}rfallbedingungen bei verschiedenen Versagensmoden}, year = {1991}, language = {de} } @article{Staat2002, author = {Staat, Manfred}, title = {Some Achievements of the European Project LISA for FEM Based Limit and Shakedown Analysis}, series = {Computational mechanics : developments and applications, 2002 : presented at the 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9. / Badie, N. [ed]}, journal = {Computational mechanics : developments and applications, 2002 : presented at the 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9. / Badie, N. [ed]}, publisher = {American Society of Mechanical Engineers}, address = {New York}, isbn = {0791846520}, pages = {177 -- 185}, year = {2002}, language = {en} }