Refine
Year of publication
Document Type
- Conference Proceeding (161) (remove)
Keywords
- Finite-Elemente-Methode (11)
- Einspielen <Werkstoff> (6)
- shakedown analysis (6)
- Clusterion (4)
- Limit analysis (4)
- Sonde (4)
- limit analysis (4)
- solar sail (4)
- Air purification (3)
- Eisschicht (3)
- Hämoglobin (3)
- Luftreiniger (3)
- MASCOT (3)
- Plasmacluster ion technology (3)
- Raumluft (3)
- Shakedown (3)
- Shakedown analysis (3)
- Traglast (3)
- Bruchmechanik (2)
- Einspielanalyse (2)
- Erythrozyt (2)
- FEM (2)
- GOSSAMER-1 (2)
- Kohlenstofffaser (2)
- Lipopolysaccharide (2)
- Ratcheting (2)
- Spacecraft (2)
- Stickstoffmonoxid (2)
- Traglastanalyse (2)
- Trajectory Optimization (2)
- celldrum technology (2)
- lipopolysaccharides (2)
- multiple NEA rendezvous (2)
- nitric oxide gas (2)
- ratchetting (2)
- shakedown (2)
- small spacecraft (2)
- Adsorption (1)
- Analytischer Zulaessigkeitsnachweis (1)
- Anastomose (1)
- Anastomosis (1)
- Antarctica (1)
- Asteroid Deflection (1)
- Attitude dynamics (1)
- Autofluoreszenzverfahren (1)
- Automated Optimization (1)
- Bakterien (1)
- Biomechanics (1)
- Biomechanik (1)
- Biomedizinische Technik (1)
- Chance constrained programming (1)
- Dattel (1)
- Dekontamination (1)
- Druckbeanspruchung (1)
- Druckbehälter (1)
- Druckbelastung (1)
- EEG (1)
- Einspiel-Analyse (1)
- Elastodynamik (1)
- Elektrodynamik (1)
- Endothelzelle (1)
- Evolution of damage (1)
- Evolutionary Neurocontrol (1)
- Exact Ilyushin yield surface (1)
- Extension fracture (1)
- Extension strain criterion (1)
- FEM-Programm (1)
- FEM-computation (1)
- Fehlerstellen (1)
- Festkörper (1)
- Fibroblast (1)
- Finite element method (1)
- First Order Reliabiblity Method (1)
- First-order reliability method (1)
- Force (1)
- Gossamer (1)
- Gossamer structures (1)
- Hybrid Propellants (1)
- Hydrodynamik (1)
- Hydrogel (1)
- Impedance Spectroscopy (1)
- Interplanetary flight (1)
- Iterative learning control (1)
- Jupiter (1)
- Knee (1)
- Körpertemperatur (1)
- LISA (1)
- Lichtstreuungsbasierte Instrumente (1)
- Load modeling (1)
- Low-Thrust Propulsion (1)
- Mars (1)
- Mechanische Beanspruchung (1)
- Mohr–Coulomb criterion (1)
- Multi-dimensional wave propagation (1)
- Multiphase (1)
- Natriumhypochlorit (1)
- Nichtlineare Gleichung (1)
- Nichtlineare Optimierung (1)
- Nichtlineare Welle (1)
- Orbital dynamics (1)
- PFM (1)
- PHILAE (1)
- Pflanzenphysiologie (1)
- Pflanzenscanner (1)
- Planetary Protection (1)
- Planetary exploration (1)
- Proteine (1)
- Random variable (1)
- Reliability of structures (1)
- Reusable Rocket Engines (1)
- Rohr (1)
- Rohrbruch (1)
- Sensitivity (1)
- Sepsis (1)
- Sequence-Search (1)
- Sleep EEG (1)
- Small Solar System Body Lander (1)
- Small Spacecraft (1)
- Solar Power Sail (1)
- Solar Sail (1)
- Solar sail (1)
- Spacecraft Trajectory Optimization (1)
- Stahl (1)
- Stochastic programming (1)
- Technische Mechanik (1)
- Torsion (1)
- Torsionsbelastung (1)
- Tragfähigkeit (1)
- Training (1)
- Wasserbrücke (1)
- Wasserstoffperoxid (1)
- Wellen (1)
- Zug-Druck-Beanspruchung (1)
- Zug-Druck-Belastung (1)
- activated nanostructured carbon (1)
- aktivierte nanostrukturierte Kohlenstofffaser (1)
- asteroid lander (1)
- asteroid sample return (1)
- autofluorescence-based detection system (1)
- biopotential electrodes (1)
- burst pressure (1)
- burst tests (1)
- contractile tension (1)
- cytosolic water diffusion (1)
- date palm tree (1)
- design-by-analysis (1)
- finite element analysis (1)
- flaw (1)
- flotilla missions (1)
- habitability (1)
- heliosphere (1)
- hemoglobin (1)
- hemoglobin dynamics (1)
- hydrogel (1)
- ice moons (1)
- icy moons (1)
- ion propulsion (1)
- kontraktile Spannung (1)
- life detection (1)
- light scattering analysis (1)
- limit and shakedown analysis (1)
- limit load (1)
- linear kinematic hardening (1)
- load carrying capacity (1)
- load limit (1)
- low-thrust (1)
- low-thrust trajectory optimization (1)
- lower bound theorem (1)
- material shakedown (1)
- mechanical waves (1)
- nanostructured carbonized plant parts (1)
- nanostrukturierte carbonisierte Pflanzenteile (1)
- near-Earth asteroid (1)
- nonlinear kinematic hardening (1)
- nonlinear optimization (1)
- nonlinear solids (1)
- nonlinear tensor constitutive equation (1)
- pipes (1)
- planetary defence (1)
- plant scanner (1)
- plasma generated ions (1)
- plastic deformation (1)
- probabilistic fracture mechanics (1)
- protein (1)
- reliability (1)
- responsive space (1)
- rhAPC (1)
- sample return (1)
- second-order reliability method (1)
- sensors (1)
- small solar system body characterisation (1)
- small spacecraft asteroid lander (1)
- small spacecraft solar sail (1)
- solar sails (1)
- solar system (1)
- space missions (1)
- subglacial aquatic ecosystems (1)
- subsurface ice (1)
- subsurface ice research (1)
- subsurface probe (1)
- system engineering (1)
- tension–torsion loading (1)
- underwater vehicle (1)
- vessels (1)
- water bridge phenomenon (1)
Effective training requires high muscle forces potentially leading to training-induced injuries. Thus, continuous monitoring and controlling of the loadings applied to the musculoskeletal system along the motion trajectory is required. In this paper, a norm-optimal iterative learning control algorithm for the robot-assisted training is developed. The algorithm aims at minimizing the external knee joint moment, which is commonly used to quantify the loading of the medial compartment. To estimate the external knee joint moment, a musculoskeletal lower extremity model is implemented in OpenSim and coupled with a model of an industrial robot and a force plate mounted at its end-effector. The algorithm is tested in simulation for patients with varus, normal and valgus alignment of the knee. The results show that the algorithm is able to minimize the external knee joint moment in all three cases and converges after less than seven iterations.
We propose a stochastic programming method to analyse limit and shakedown of structures under random strength with lognormal distribution. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit or the shakedown limit. The edge-based smoothed finite element method (ES-FEM) using three-node linear triangular elements is used.
Electromechanical model of hiPSC-derived ventricular cardiomyocytes cocultured with fibroblasts
(2018)
The CellDrum provides an experimental setup to study the mechanical effects of fibroblasts co-cultured with hiPSC-derived ventricular cardiomyocytes. Multi-scale computational models based on the Finite Element Method are developed. Coupled electrical cardiomyocyte-fibroblast models (cell level) are embedded into reaction-diffusion equations (tissue level) which compute the propagation of the action potential in the cardiac tissue. Electromechanical coupling is realised by an excitation-contraction model (cell level) and the active stress arising during contraction is added to the passive stress in the force balance, which determines the tissue displacement (tissue level). Tissue parameters in the model can be identified experimentally to the specific sample.
The overall objective of this study is to develop a new external fixator, which closely maps the native kinematics of the elbow to decrease the joint force resulting in reduced rehabilitation time and pain. An experimental setup was designed to determine the native kinematics of the elbow during flexion of cadaveric arms. As a preliminary study, data from literature was used to modify a published biomechanical model for the calculation of the joint and muscle forces. They were compared to the original model and the effect of the kinematic refinement was evaluated. Furthermore, the obtained muscle forces were determined in order to apply them in the experimental setup. The joint forces in the modified model differed slightly from the forces in the original model. The muscle force curves changed particularly for small flexion angles but their magnitude for larger angles was consistent.
The vaginal prolapse after hysterectomy (removal of the uterus) is often associated with the prolapse of the vaginal vault, rectum, bladder, urethra or small bowel. Minimally
invasive surgery such as laparoscopic sacrocolpopexy and pectopexy are widely performed for the treatment of the vaginal prolapse with weakly supported vaginal vault after hysterectomy using prosthetic mesh implants to support (or strengthen) lax apical ligaments. Implants of different shape, size and polymers are selected depending on the patient’s anatomy and the surgeon’s preference. In this computational study on pectopexy, DynaMesh®-PRP soft, GYNECARE GYNEMESH® PS Nonabsorbable PROLENE® soft and Ultrapro® are tested in a 3D finite element model of the female pelvic floor. The mesh model is implanted into the extraperitoneal space and sutured to the vaginal stump with a bilateral fixation to the iliopectineal ligament at both sides. Numerical simulations are conducted at rest, after surgery and during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues and prosthetic meshes are modeled as incompressible, isotropic hyperelastic materials. The positions of the organs are calculated with respect to the pubococcygeal line (PCL) for female pelvic floor at rest, after repair and during Valsalva maneuver using the three meshes.
Recent analysis of scientific data from Cassini and earth-based observations gave evidence for a global ocean under a surrounding solid ice shell on Saturn's moon Enceladus. Images of Enceladus' South Pole showed several fissures in the ice shell with plumes constantly exhausting frozen water particles, building up the E-Ring, one of the outer rings of Saturn. In this southern region of Enceladus, the ice shell is considered to be as thin as 2 km, about an order of magnitude thinner than on the rest of the moon. Under the ice shell, there is a global ocean consisting of liquid water. Scientists are discussing different approaches the possibilities of taking samples of water, i.e. by melting through the ice using a melting probe. FH Aachen UAS developed a prototype of maneuverable melting probe which can navigate through the ice that has already been tested successfully in a terrestrial environment. This means no atmosphere and or ambient pressure, low ice temperatures of around 100 to 150K (near the South Pole) and a very low gravity of 0,114 m/s^2 or 1100 μg. Two of these influencing measures are about to be investigated at FH Aachen UAS in 2017, low ice temperature and low ambient pressure below the triple point of water. Low gravity cannot be easily simulated inside a large experiment chamber, though. Numerical simulations of the melting process at RWTH Aachen however are showing a gravity dependence of melting behavior. Considering this aspect, VIPER provides a link between large-scale experimental simulations at FH Aachen UAS and numerical simulations at RWTH Aachen. To analyze the melting process, about 90 seconds of experiment time in reduced gravity and low ambient pressure is provided by the REXUS rocket. In this time frame, the melting speed and contact force between ice and probes are measured, as well as heating power and a two-dimensional array of ice temperatures. Additionally, visual and infrared cameras are used to observe the melting process.
The quest for life on other planets is closely connected with the search for water in liquid state. Recent discoveries of deep oceans on icy moons like Europa and Enceladus have spurred an intensive discussion about how these waters can be accessed. The challenge of this endeavor lies in the unforeseeable requirements on instrumental characteristics both with respect to the scientific and technical methods. The TRIPLE/nanoAUV initiative is aiming at developing a mission concept for exploring exo-oceans and demonstrating the achievements in an earth-analogue context, exploring the ocean under the ice shield of Antarctica and lakes like Dome-C on the Antarctic continent.
Physical interaction with small solar system bodies (SSSB) is the next step in planetary science, planetary in-situ resource utilization (ISRU), and planetary defense (PD). It requires a broader understanding of the surface properties of the target objects, with particular interest focused on those near Earth. Knowledge of composition, multi-scale surface structure, thermal response, and interior structure is required to design, validate and operate missions addressing these three fields. The current level of understanding is occasionally simplified into the phrase, ”If you’ve seen one asteroid, you’ve seen one asteroid”, meaning that the in-situ characterization of SSSBs has yet to cross the threshold towards a robust and stable scheme of classification. This would enable generic features in spacecraft design, particularly for ISRU and science missions. Currently, it is necessary to characterize any potential target object sufficiently by a dedicated pre-cursor mission to design the mission which then interacts with the object in a complex fashion. To open up strategic approaches, much broader in-depth characterization of potential target objects would be highly desirable. In SSSB science missions, MASCOT-like nano-landers and instrument carriers which integrate at the instrument level to their mothership have met interest. By its size, MASCOT is compatible with small interplanetary missions. The DLR-ESTEC Gossamer Roadmap Science Working Groups‘ studies identified Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the space science missions only feasible with solar sail propulsion. The Solar Polar Orbiter (SPO) study showed the ability to access any inclination, theDisplaced-L1 (DL1) mission operates close to Earth, where objects of interest to PD and for ISRU reside. Other studies outline the unique capability of solar sails to provide access to all SSSB, at least within the orbit of Jupiter, and significant progress has been made to explore the performance envelope of near-term solar sails for MNR. However, it is difficult for
sailcraft to interact physically with a SSSB. We expand and extend the philosophy of the recently qualified DLR Gossamer solar sail deployment technology using efficient multiple sub-spacecraft integration to also include landers for one-way in-situ investigations and sample-return missions by synergetic integration and operation of sail and lander. The MASCOT design concept and its characteristic features have created an ideal counterpart for thisand has already been adapted to the needs of the AIM spacecraft, former part of the NASA-ESA AIDA missionDesigning the 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. IAC-18-F1.2.3 Page 2 of 17 combined spacecraft for piggy-back launch accommodation enables low-cost massively parallel access to the NEA population.