TY  - JOUR
A1  - Campen, R.
A1  - Kowalski, Julia
A1  - Lyons, W.B.
A1  - Tulaczyk, S.
A1  - Dachwald, Bernd
A1  - Pettit, E.
A1  - Welch, K. A.
A1  - Mikucki, J.A.
T1  - Microbial diversity of an Antarctic subglacial community and high‐resolution replicate sampling inform hydrological connectivity in a polar desert
JF  - Environmental Microbiology
Y1  - 2019
U6  - https://doi.org/10.1111/1462-2920.14607
SN  - 1462-2920
IS  - accepted article
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Multiple Near-Earth Asteroid Rendezvous and Sample Return Using First Generation Solar Sailcraft
JF  - Acta Astronautica. 57 (2005), H. 11
Y1  - 2005
SN  - 0094-5765
SP  - 864
EP  - 875
ER  - 
TY  - JOUR
A1  - Schael, S.
A1  - Atanasyan, A.
A1  - Berdugo, J.
A1  - Bretz, T.
A1  - Czupalla, Markus
A1  - Dachwald, Bernd
A1  - Doetinchem, P. von
A1  - Duranti, M.
A1  - Gast, H.
A1  - Karpinski, W.
A1  - Kirn, T.
A1  - Lübelsmeyer, K.
A1  - Maña, C.
A1  - Marrocchesi, P.S.
A1  - Mertsch, P.
A1  - Moskalenko, I.V.
A1  - Schervan, T.
A1  - Schluse, M.
A1  - Schröder, K.-U.
A1  - Schultz von Dratzig, A.
A1  - Senatore, C.
A1  - Spies, L.
A1  - Wakely, S.P.
A1  - Wlochal, M.
A1  - Uglietti, D.
A1  - Zimmermann, J.
T1  - AMS-100: The next generation magnetic spectrometer in space – An international science platform for physics and astrophysics at Lagrange point 2
JF  - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Y1  - 2019
U6  - https://doi.org/10.1016/j.nima.2019.162561
SN  - 0168-9002
VL  - 944
IS  - 162561
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Solar sailcraft of the first generation mission applications to near-earth asteroids
Y1  - 2003
N1  - 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September - 3 October 2003, Bremen, Germany IAC-03-Q.5.06
ER  - 
TY  - JOUR
A1  - Kowalski, Julia
A1  - Linder, Peter
A1  - Zierke, S.
A1  - Wulfen, B. van
A1  - Clemens, J.
A1  - Konstantinidis, K.
A1  - Ameres, G.
A1  - Hoffmann, R.
A1  - Mikucki, J.
A1  - Tulaczyk, S.
A1  - Funke, O.
A1  - Blandfort, D.
A1  - Espe, Clemens
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Hiecker, S.
A1  - Plescher, Engelbert
A1  - Schöngarth, Sarah
A1  - Dachwald, Bernd
A1  - Digel, Ilya
A1  - Artmann, Gerhard
A1  - Eliseev, D.
A1  - Heinen, D.
A1  - Scholz, F.
A1  - Wiebusch, C.
A1  - Macht, S.
A1  - Bestmann, U.
A1  - Reineking, T.
A1  - Zetzsche, C.
A1  - Schill, K.
A1  - Förstner, R.
A1  - Niedermeier, H.
A1  - Szumski, A.
A1  - Eissfeller, B.
A1  - Naumann, U.
A1  - Helbing, K.
T1  - Navigation technology for exploration of glacier ice with maneuverable melting probes
JF  - Cold Regions Science and Technology
N2  - The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept.
Y1  - 2016
U6  - https://doi.org/10.1016/j.coldregions.2015.11.006
SN  - 0165-232X
IS  - 123
SP  - 53
EP  - 70
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Götten, Falk
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Marino, Matthew
A1  - Bil, Cees
T1  - Aerodynamic Investigations of UAV Sensor Turrets - A Combined Wind-tunnel and CFD Approach
JF  - SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021
Y1  - 2021
U6  - https://doi.org/10.2514/6.2021-1535
SP  - 1
EP  - 12
PB  - AIAA
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimization of very-low-thrust trajectories using evolutionary neurocontrol
JF  - Acta Astronautica
N2  - 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).
Y1  - 2005
SN  - 1879-2030
VL  - 57
IS  - 2-8
SP  - 175
EP  - 185
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Götten, Falk
A1  - Finger, Felix
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Marino, M.
A1  - Bil, C.
T1  - Full configuration drag estimation of short-to-medium range fixed-wing UAVs and its impact on initial sizing optimization
JF  - CEAS Aeronautical Journal
N2  - The paper presents the derivation of a new equivalent skin friction coefficient for estimating the parasitic drag of short-to-medium range fixed-wing unmanned aircraft. The new coefficient is derived from an aerodynamic analysis of ten different unmanned aircraft used for surveillance, reconnaissance, and search and rescue missions. The aircraft is simulated using a validated unsteady Reynolds-averaged Navier Stokes approach. The UAV’s parasitic drag is significantly influenced by the presence of miscellaneous components like fixed landing gears or electro-optical sensor turrets. These components are responsible for almost half of an unmanned aircraft’s total parasitic drag. The new equivalent skin friction coefficient accounts for these effects and is significantly higher compared to other aircraft categories. It is used to initially size an unmanned aircraft for a typical reconnaissance mission. The improved parasitic drag estimation yields a much heavier unmanned aircraft when compared to the sizing results using available drag data of manned aircraft.
KW  - Parasitic drag
KW  - UAV
KW  - CFD
KW  - Aircraft sizing
Y1  - 2021
U6  - https://doi.org/10.1007/s13272-021-00522-w
SN  - 1869-5590 (Online)
SN  - 1869-5582 (Print)
N1  - Corresponding author: Falk Götten
VL  - 12
SP  - 589
EP  - 603
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Finger, Felix
A1  - Bil, Cees
A1  - Braun, Carsten
T1  - Initial Sizing Methodology for Hybrid-Electric General Aviation Aircraft
JF  - Journal of Aircraft
Y1  - 2019
U6  - https://doi.org/10.2514/1.C035428
SN  - 1533-3868
VL  - 57
IS  - 2
SP  - 245
EP  - 255
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Beckmann, Nils
A1  - Keinz, Jan
A1  - Abanteriba, Sylvester
T1  - Numerical and Experimental Evaluation of a Dual-Fuel Dry-Low-NOx Micromix Combustor for Industrial Gas Turbine Applications
JF  - Journal of Thermal Science and Engineering Applications
Y1  - 2019
U6  - https://doi.org/10.1115/1.4041495
SN  - 19485085
N1  - Paper No: GT2017-64795
VL  - 11
IS  - 1
SP  - 011015
PB  - ASME
CY  - New York
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Optimizing low-thrust gravity assist interplanetary trajectories using evolutionary neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile
JF  - IEEE Congress on Evolutionary Computation, 2007 : CEC 2007 ; 25 - 28 September 2007, Singapore
Y1  - 2007
SN  - 978-1-424-41339-3
N1  - ISBN 10: 1-424-41339-7 ; IEEE Congress on Evolutionary Computation <2007, Singapore> ; 	Institute of Electrical and Electronics Engineers ; Nebent: CEC 2007 ; Parallel als Online-Ausg. erschienen
SP  - 965
EP  - 972
PB  - IEEE Service Center
CY  - Piscataway, NJ
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Mikucki, Jill
A1  - Tulaczyk, Slawek
A1  - Digel, Ilya
A1  - Espe, Clemens
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Kowalski, Julia
A1  - Xu, Changsheng
T1  - IceMole : A maneuverable probe for clean in situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems
JF  - Annals of Glaciology
N2  - There is significant interest in sampling subglacial environments for geobiological studies, but they are difficult to access. Existing ice-drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The IceMole is a maneuverable subsurface ice probe for clean in situ analysis and sampling of glacial ice and subglacial materials. The design is based on the novel concept of combining melting and mechanical propulsion. It can change melting direction by differential heating of the melting head and optional side-wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland. They demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. A more advanced probe is currently under development as part of the Enceladus Explorer (EnEx) project. It offers systems for obstacle avoidance, target detection, and navigation in ice. For the EnEx-IceMole, we will pay particular attention to clean protocols for the sampling of subglacial materials for biogeochemical analysis. We plan to use this probe for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, with return of a subglacial brine sample.
KW  - Antarctic Glaciology
KW  - Extraterrestrial Glaciology
KW  - Glaciological instruments and methods
KW  - Subclacial exploration
KW  - Subglacial lakes
Y1  - 2014
U6  - https://doi.org/10.3189/2014AoG65A004
SN  - 1727-5644
VL  - 55
IS  - 65
SP  - 14
EP  - 22
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - McDonald, Malcolm
A1  - McInnes, Colin R.
A1  - Mengali, Giovanni
T1  - Impact of Optical Degradation on Solar Sail Mission Performance
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 4
Y1  - 2007
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 740
EP  - 749
ER  - 
TY  - JOUR
A1  - Konstantinidis, Konstantinos
A1  - Flores Martinez, Claudio
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Dykta, Paul
A1  - Bowitz, Pascal
A1  - Rudolph, Martin
A1  - Digel, Ilya
A1  - Kowalski, Julia
A1  - Voigt, Konstantin
A1  - Förstner, Roger
T1  - A lander mission to probe subglacial water on Saturn's moon enceladus for life
JF  - Acta astronautica
Y1  - 2015
SN  - 1879-2030 (E-Journal); 0094-5765 (Print)
VL  - Vol. 106
SP  - 63
EP  - 89
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ulamec, Stephan
A1  - Postberg, Frank
A1  - Sohl, Frank
A1  - Vera, Jean-Pierre de
A1  - Christoph, Waldmann
A1  - Lorenz, Ralph D.
A1  - Hellard, Hugo
A1  - Biele, Jens
A1  - Rettberg, Petra
T1  - Key technologies and instrumentation for subsurface exploration of ocean worlds
JF  - Space Science Reviews
N2  - In this chapter, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed. The focus is laid on Jupiter’s moon Europa and Saturn’s moon Enceladus because they have the highest potential for such missions in the near future. The exploration of their oceans requires landing on the surface, penetrating the thick ice shell with an ice-penetrating probe, and probably diving with an underwater vehicle through dozens of kilometers of water to the ocean floor, to have the chance to find life, if it exists. Technologically, such missions are extremely challenging. The required key technologies include power generation, communications, pressure resistance, radiation hardness, corrosion protection, navigation, miniaturization, autonomy, and sterilization and cleaning. Simpler mission concepts involve impactors and penetrators or – in the case of Enceladus – plume-fly-through missions.
Y1  - 2020
U6  - https://doi.org/10.1007/s11214-020-00707-5
SN  - 1572-9672
N1  - Corresponding author: Bernd Dachwald
VL  - 216
IS  - Art. 83
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wi, Bong
T1  - Solar Sail Kinetic Energy Impactor Trajectory Optimization for an Asteroid-Deflection Mission
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 4
Y1  - 2007
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 755
EP  - 764
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Minimum Transfer Times for Nonperfectly Reflecting Solar Sailcraft
JF  - Journal of Spacecraft and Rockets. 41 (2004), H. 4
Y1  - 2004
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 693
EP  - 695
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimization of Interplanetary Solar Sailcraft Trajectories Using Evolutionary Neurocontrol
JF  - Journal of guidance, control, and dynamics. 27 (2004), H. 1
Y1  - 2004
SN  - 0162-3192
N1  - 2. ISSN: 0162-3192. - 3. ISSN: 0731-5090
SP  - 66
EP  - 72
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ohndorf, A.
A1  - Gill, E.
T1  - Optimization of low-thrust Earth-Moon transfers using evolutionary neurocontrol  / Ohndorf, A. ; Dachwald, B. ; Gill, E.
JF  - IEEE Congress on Evolutionary Computation, 2009. CEC '09.
Y1  - 2009
SN  - 978-1-4244-2958-5
SP  - 358
EP  - 364
ER  - 
TY  - JOUR
A1  - Scholz, Christina
A1  - Romagnoli, Daniele
A1  - Dachwald, Bernd
A1  - Theil, Stephan
T1  - Performance analysis of an attitude control system for solar sails using sliding masses
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1822
EP  - 1835
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Leipold, M.
A1  - Fichtner, H.
A1  - Heber, B.
A1  - Groepper, P.
A1  - Lascar, S.
A1  - Burger, F.
A1  - Eiden, M.
A1  - Niederstadt, T.
A1  - Sickinger, C.
A1  - Herbeck, L.
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System
JF  - Acta Astronautica. 59 (2006), H. 8-11
Y1  - 2006
SN  - 0094-5765
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; Selected Proceedings
SP  - 786
EP  - 796
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Turyshev, Slava G.
A1  - Dittus, H.
A1  - Shao, M. [u.a.]
T1  - Fundamental Physics with the Laser Astrometric Test Of Relativity / S.G. Turyshev ;  H. Dittus ; M. Shao ... B.Dachwald ...
JF  - Proceedings of the 39th ESLAB Symposium "Trends in Space Science and Cosmic Vision 2020" : 19 - 21 April 2005, ESTEC, Noordwijk, the Netherlands / European Space Agency. [Comp. by: F. Favata ...] . - (ESA SP ; 588)
Y1  - 2005
SN  - 9290928999
N1  - ISBN der CD-ROM-Ausg.: 9290928999 ; Symposium Trends in Space Science and Cosmic Vision 2020 <2005, Noordwijk> ; ESLAB symposium <39, 2005, Noordwijk> ; European Space Laboratory
SP  - 8
EP  - 11
PB  - ESA Publ. Div.
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Dittus, H.
A1  - Turyshev, S. G.
A1  - Dachwald, Bernd
A1  - Blome, Hans-Joachim
T1  - A Mission to Explore the Pioneer Anomaly
JF  - Proceedings of the 39th ESLAB Symposium "Trends in Space Science and Cosmic Vision 2020" : 19 - 21 April 2005, ESTEC, Noordwijk, the Netherlands / European Space Agency. [Comp. by: F. Favata ...] . - (ESA SP ; 588)
Y1  - 2005
SN  - 9290928999
N1  - ISBN der CD-ROM-Ausg.: 9290928999 ; Symposium Trends in Space Science and Cosmic Vision 2020 <2005, Noordwijk> ; ESLAB symposium <39,2005, Noordwijk> ; European Space Laboratory ; Report Number: LA-UR-05-4907 ; The Pioneer Explorer Collaboration
SP  - 3
EP  - 10
PB  - ESA Publ. Div.
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - MacDonald, Malcolm
A1  - McInnes, Colin R.
T1  - Heliocentric Solar Sail Orbit Transfers with Locally Optimal Control Laws / Malcolm Macdonald ; Colin McInnes ; Bernd Dachwald
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 1
Y1  - 2007
SN  - 0022-4650
SP  - 273
EP  - 276
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Solar Sails for Near- and Medium-Term Scientific Deep Space Missions / W. Sebolt ; B. Dachwald
JF  - In-space propulsion : edited book of proceedings of the 10-IWCP, the 10th International Workshop on Combustion and Propulsion held in Lerici, La Spezia, Italy, 21-25 September 2003 / [ed.: Luigi T. DeLuca]
Y1  - 2005
N1  - Paper 31 ; International workshop on combustion and propulsion <10, 2003, Lerici>
PB  - SP Lab, Politecnico di Milano
CY  - Milano
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Evolutionary Neurocontrol as a Novel Method for Low-Thrust Gravity Assist Trajectory Optimization / I. Carnelli ; B. Dachwald ; M. Vasile
JF  - Proceedings of the Twenty-Fifth International Symposium on Space Technology and Science (Selected papers) : Kanazawa, [June 4 through June 11, 2006, at Kanazawa-shi Kanko Kaikan in Kanazawa city] / [Japan Society for Aeronautical and Space Sciences. Kohtaro Matsumoto [ed.-in-chief]
Y1  - 2006
SN  - 4-99005-002-9
N1  - International Symposium on Space Technology and Science <25, 2006, Kanazawa> ; ISTS 2006-d-46
SP  - 569
EP  - 574
PB  - JSASS
CY  - Tokyo
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Low-Thrust Gravity Assist Trajectory Optimization Using Evolutionary Neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile ...
JF  - Astrodynamics 2005 : proceedings of the AAS/AIAA astrodynamics conference held August 7 - 11, 2005, South Lake Tahoe, California / ed. by Bobby G. Williams. - Pt. 3. - (Advances in the astronautical sciences ; 123,3)
Y1  - 2006
SN  - 0-87703-527-X
N1  - Astrodynamics Conference <2005, South Lake Tahoe, Calif.> ; American Astronautical Society ; Number: AAS-05-374
SP  - 1911
EP  - 1928
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Leipold, M.
A1  - Fichtner, H.
T1  - Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System / M. Leipold ; H. Fichtner ; B. Heber  ... B. Dachwald ...
JF  - Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]
Y1  - 2003
SN  - 92-9092-853-0
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; International Academy of Astronautics ; European Space Research and Technology Centre
SP  - 367
EP  - 375
PB  - ESA
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Interplanetary Mission Analysis for Non-Perfectly Reflecting Solar Sailcraft Using Evolutionary Neurocontrol
JF  - Astrodynamics 2003 : proceedings of the AAS/AIAA Astrodynamics Conference held August 3 - 7, 2003, Big Sky, Montana / ed. by Jean de Lafontaine. - Pt. 2. - (Advances in the astronautical sciences ; 116,2)
Y1  - 2004
SN  - 0-87703-509-1
N1  - Astrodynamics Conference <2003, Big Sky, Mont.> ; American Institute of Aeronautics and Astronautics <Reston, Va.> ; AAS-03-579
SP  - 1247
EP  - 1262
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Optimization of Interplanetary Rendezvous Trajectories for Solar Sailcraft Using a Neurocontroller
JF  - A collection of technical papers / AIAA Astrodynamics Specialist Conference : Monterey, California, 5 - 8 August 2002. - Vol. 2
Y1  - 2002
SN  - 1-56347-549-9
N1  - Astrodynamics Specialist Conference <2002, Monterey, Calif.> American Institute of Aeronautics and Astronautics <Reston, Va.>  ; AIAA  paper number: AIAA-2002-4989
SP  - 1263
EP  - 1270
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Schirra, Julian
A1  - Bissonnette, William
A1  - Bramesfeld, Götz
T1  - Wake-model effects on induced drag prediction of staggered boxwings
JF  - Aerospace
Y1  - 2018
U6  - https://doi.org/10.3390/aerospace5010014
SN  - 2226-4310
VL  - 5
IS  - 1
ER  - 
TY  - JOUR
A1  - Kreyer, Jörg
A1  - Müller, Marvin
A1  - Esch, Thomas
T1  - A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles
JF  - SAE International Journal of Commercial Vehicles
N2  - The predictive control of commercial vehicle energy management systems, such as vehicle thermal management or waste heat recovery (WHR) systems, are discussed on the basis of information sources from the field of environment recognition and in combination with the determination of the vehicle system condition.
In this article, a mathematical method for predicting the exhaust gas mass flow and the exhaust gas temperature is presented based on driving data of a heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated on the motorway to investigate the characteristic operational profile. In addition to the use of road gradient profile data, an evaluation of the continuously recorded distance signal, which represents the distance between the test vehicle and the road user ahead, is included in the prediction model. Using a Fourier analysis, the trajectory of the vehicle speed is determined for a defined prediction horizon.
To verify the method, a holistic simulation model consisting of several hierarchically structured submodels has been developed. A map-based submodel of a combustion engine is used to determine the EGR and EAT exhaust gas mass flows and exhaust gas temperature profiles. All simulation results are validated on the basis of the recorded vehicle and environmental data. Deviations from the predicted values are analyzed and discussed.
Y1  - 2020
U6  - https://doi.org/10.4271/02-13-02-0009
SN  - 1946-3928
VL  - 13
IS  - 2
SP  - 129
EP  - 143
PB  - SAE International
CY  - Warrendale, Pa.
ER  - 
TY  - JOUR
A1  - Meyer, Max-Arno
A1  - Granrath, Christian
A1  - Feyerl, Günter
A1  - Richenhagen, Johannes
A1  - Kaths, Jakob
A1  - Andert, Jakob
T1  - Closed-loop platoon simulation with cooperative intelligent transportation systems based on vehicle-to-X communication
JF  - Simulation Modelling Practice and Theory
Y1  - 2021
U6  - https://doi.org/10.1016/j.simpat.2020.102173
SN  - 1569-190X
VL  - 106
IS  - Art. 102173
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Gazda, Quentin
A1  - Maurischat, Andreas
T1  - Special functions and Gauss-Thakur sums in higher rank and dimension
Y1  - 2020
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Khayyam, Hamid
A1  - Jamali, Ali
A1  - Bab-Hadiashar, Alireza
A1  - Esch, Thomas
A1  - Ramakrishna, Seeram
A1  - Jalil, Mahdi
A1  - Naebe, Minoo
T1  - A Novel Hybrid Machine Learning Algorithm for Limited and Big Data Modelling with Application in Industry 4.0
JF  - IEEE Access
N2  - To meet the challenges of manufacturing smart products, the manufacturing plants have been radically changed to become smart factories underpinned by industry 4.0 technologies. The transformation is assisted by employment of machine learning techniques that can deal with modeling both big or limited data. This manuscript reviews these concepts and present a case study that demonstrates the use of a novel intelligent hybrid algorithms for Industry 4.0 applications with limited data. In particular, an intelligent algorithm is proposed for robust data modeling of nonlinear systems based on input-output data. In our approach, a novel hybrid data-driven combining the Group-Method of Data-Handling and Singular-Value Decomposition is adapted to find an offline deterministic model combined with Pareto multi-objective optimization to overcome the overfitting issue. An Unscented-Kalman-Filter is also incorporated to update the coefficient of the deterministic model and increase its robustness against data uncertainties. The effectiveness of the proposed method is examined on a set of real industrial measurements.
Y1  - 2020
SN  - 2169-3536
U6  - https://doi.org/10.1109/ACCESS.2020.2999898
SP  - 1
EP  - 12
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Hailer, Benjamin
A1  - Weber, Tobias
A1  - Neveling, Sebastian
A1  - Dera, Samuel
A1  - Arent, Jan-Christoph
A1  - Middendorf, Peter
T1  - Development of a test device to determine the frictional behavior between honeycomb and prepreg layers under realistic manufacturing conditions
JF  - Journal of Sandwich Structures & Materials
N2  - In the friction tests between honeycomb with film adhesive and prepreg, the relative displacement occurs between the film adhesive and the prepreg. The film adhesive does not shift relative to the honeycomb. This is consistent with the core crush behavior where the honeycomb moves together with the film adhesive, as can be seen in Figure 2(a). The pull-through forces of the friction measurements between honeycomb and prepreg at 1 mm deformation are plotted in Figure 17(a). While the friction at 100°C is similar to the friction at 120°C, it decreases significantly at 130°C and exhibits a minimum at 140°C. At 150°C, the friction rises again slightly and then sharply at 160°C. Since the viscosity of the M18/1 prepreg resin drops significantly before it cures [23], the minimum friction at 140°C could result from a minimum viscosity of the mixture of prepreg resin and film adhesive before the bond subsequently cures. Figure 17(b) shows the mean value curve of the friction measurements at 140°C. The error bars, which represent the standard deviation, reveal the good repeatability of the tests. The force curve is approximately horizontal between 1 mm and 2 mm. The friction then slightly rises. As with interlaminar friction measurements, this could be due to the fact that resin is removed by friction and the proportion of boundary lubrication increases. Figure 18 shows the surfaces after the friction measurement. The honeycomb cell walls are clearly visible in the film adhesive. There are areas where the film adhesive is completely removed and the carrier material of the film adhesive becomes visible. In addition, the viscosity of the resin changes as the curing progresses during the friction test. This can also affect the force-displacement curve.
Y1  - 2020
U6  - https://doi.org/10.1177/1099636220923986
SN  - 1530-7972
IS  - Volume 23, Issue 7
SP  - 3017
EP  - 3043
PB  - Sage
CY  - London
ER  - 
TY  - JOUR
A1  - Maurischat, Andreas
T1  - Algebraic independence of the Carlitz period and its hyperderivatives
JF  - Journal of Number Theory
KW  - Drinfeld modules
KW  - Periods
KW  - t-modules
KW  - Transcendence
KW  - Higher derivations
Y1  - 2022
U6  - https://doi.org/10.1016/j.jnt.2022.01.006
SN  - 0022-314X
VL  - 240
SP  - 145
EP  - 162
PB  - Elsevier
CY  - Orlando, Fla.
ER  - 
TY  - JOUR
A1  - Tekin, Nurettin
A1  - Ashikaga, Mitsugu
A1  - Horikawa, Atsushi
A1  - Funke, Harald
T1  - Enhancement of fuel flexibility of industrial gas turbines by development of innovative hydrogen combustion systems
JF  - Gas for energy
N2  - For fuel flexibility enhancement hydrogen represents a possible alternative gas turbine fuel within future low emission power generation, in case of hydrogen production by the use of renewable energy sources such as wind energy or biomass. Kawasaki Heavy Industries, Ltd. (KHI) has research and development projects for future hydrogen society; production of hydrogen gas, refinement and liquefaction for transportation and storage, and utilization with gas turbine / gas engine for the generation of electricity. In the development of hydrogen gas turbines, a key technology is the stable and low NOx hydrogen combustion, especially Dry Low Emission (DLE) or Dry Low NOx (DLN) hydrogen combustion. Due to the large difference in the physical properties of hydrogen compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for DLE hydrogen combustion. Thus, the development of DLE hydrogen combustion technologies is an essential and challenging task for the future of hydrogen fueled gas turbines. The DLE Micro-Mix combustion principle for hydrogen fuel has been in development for many years to significantly reduce NOx emissions. This combustion principle is based on cross-flow mixing of air and gaseous hydrogen which reacts in multiple miniaturized “diffusion-type” flames. The major advantages of this combustion principle are the inherent safety against flashback and the low NOx-emissions due to a very short residence time of the reactants in the flame region of the micro-flames.
Y1  - 2018
IS  - 2
PB  - Vulkan-Verlag
CY  - Essen
ER  - 
TY  - JOUR
A1  - Thoma, Andreas
A1  - Ravi, Sridhar
T1  - Significance of parallel computing on the performance of Digital Image Correlation algorithms in MATLAB
N2  - Digital Image Correlation (DIC) is a powerful tool used to evaluate displacements and deformations in a non-intrusive manner. By comparing two images, one of the undeformed reference state of a specimen and another of the deformed target state, the relative displacement between those two states is determined. DIC is well known and often used for post-processing analysis of in-plane displacements and deformation of specimen. Increasing the analysis speed to enable real-time DIC analysis will be beneficial and extend the field of use of this technique.
Here we tested several combinations of the most common DIC methods in combination with different parallelization approaches in MATLAB and evaluated their performance to determine whether real-time analysis is possible with these methods. To reflect improvements in computing technology different hardware settings were also analysed. We found that implementation problems can reduce the efficiency of a theoretically superior algorithm such that it becomes practically slower than a suboptimal algorithm. The Newton-Raphson algorithm in combination with a modified Particle Swarm algorithm in parallel image computation was found to be most effective. This is contrary to theory, suggesting that the inverse-compositional Gauss-Newton algorithm is superior. As expected, the Brute Force Search algorithm is the least effective method. We also found that the correct choice of parallelization tasks is crucial to achieve improvements in computing speed. A poorly chosen parallelisation approach with high parallel overhead leads to inferior performance. Finally, irrespective of the computing mode the correct choice of combinations of integerpixel and sub-pixel search algorithms is decisive for an efficient analysis. Using currently available hardware realtime analysis at high framerates remains an aspiration.
Y1  - 2019
SP  - 1
EP  - 17
ER  - 
TY  - JOUR
A1  - Weber, Tobias
A1  - Englhard, Markus
A1  - Arent, Jan-Christoph
A1  - Hausmann, Joachim
T1  - An experimental characterization of wrinkling generated during prepreg autoclave manufacturing using caul plates
JF  - Journal of Composite Materials
Y1  - 2019
U6  - https://doi.org/10.1177/0021998319846556
SN  - 1530-793X
VL  - 53
IS  - 26-27
SP  - 3757
EP  - 3773
ER  - 
TY  - JOUR
A1  - Otten, Dennis
A1  - Weber, Tobias
A1  - Arent, Jan-Christoph
T1  - Manufacturing Process Simulation – On Its Way to Industrial Application
JF  - International Journal of Aviation, Aeronautics, and Aerospace
N2  - Manufacturing process simulation (MPS) has become more and more important for aviation and the automobile industry. A highly competitive market requires the use of high performance metals and composite materials in combination with reduced manufacturing cost and time as well as a minimization of the time to market for a new product. However, the use of such materials is expensive and requires sophisticated manufacturing processes. An experience based process and tooling design followed by a lengthy trial-and-error optimization is just not contemporary anymore. Instead, a tooling design process aided by simulation is used more often. This paper provides an overview of the capabilities of MPS in the fields of sheet metal forming and prepreg autoclave manufacturing of composite parts summarizing the resulting benefits for tooling design and manufacturing engineering. The simulation technology is explained briefly in order to show several simplification and optimization techniques for developing industrialized simulation approaches. Small case studies provide examples of an efficient application on an industrial scale.
Y1  - 2018
U6  - https://doi.org/10.15394/ijaaa.2018.1217
SN  - 2374-6793
VL  - 5
IS  - 2
PB  - Embry-Riddle Aeronautical University
CY  - Daytona Beach, Fla.
ER  - 
TY  - JOUR
A1  - Weber, Tobias
A1  - Ruff-Stahl, Hans-Joachim K.
T1  - Advances in Composite Manufacturing of Helicopter Parts
JF  - International Journal of Aviation, Aeronautics, and Aerospace
Y1  - 2017
U6  - https://doi.org/10.15394/ijaaa.2017.1153
SN  - 2374-6793
VL  - 4
IS  - 1
ER  - 
TY  - JOUR
A1  - Hoeveler, B.
A1  - Bauknecht, André
A1  - Wolf, C. Christian
A1  - Janser, Frank
T1  - Wind-Tunnel Study of a Wing-Embedded Lifting Fan Remaining Open in Cruise Flight
JF  - Journal of Aircraft
N2  - It is investigated whether a nonrotating lifting fan remaining uncovered during cruise flight, as opposed to being covered by a shutter system, can be realized with limited additional drag and loss of lift during cruise flight. A wind-tunnel study of a wing-embedded lifting fan has been conducted at the Side Wind Test Facility Göttingen of DLR, German Aerospace Center in Göttingen using force, pressure, and stereoscopic particle image velocimetry techniques. The study showed that a step on the lower side of the wing in front of the lifting fan duct increases the lift-to-drag ratio of the whole model by up to 25% for all positive angles of attack. Different sizes and inclinations of the step had limited influence on the surface pressure distribution. The data indicate that these parameters can be optimized to maximize the lift-to-drag ratio. A doubling of the curvature radius of the lifting fan duct inlet lip on the upper side of the wing affected the lift-to-drag ratio by less than 1%. The lifting fan duct inlet curvature can therefore be optimized to maximize the vertical fan thrust of the rotating lifting fan during hovering without affecting the cruise flight performance with a nonrotating fan.
Y1  - 2020
U6  - https://doi.org/10.2514/1.C035422
SN  - 1533-3868
VL  - 57
IS  - 4
PB  - AIAA
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Khayyam, Hamid
A1  - Jamali, Ali
A1  - Bab-Hadiashar, Alireza
A1  - Esch, Thomas
A1  - Ramakrishna, Seeram
A1  - Jalili, Mahdi
A1  - Naebe, Minoo
T1  - A Novel Hybrid Machine Learning Algorithm for Limited and Big Data Modeling with Application in Industry 4.0
JF  - IEEE Access
N2  - To meet the challenges of manufacturing smart products, the manufacturing plants have been radically changed to become smart factories underpinned by industry 4.0 technologies. The transformation is assisted by employment of machine learning techniques that can deal with modeling both big or limited data. This manuscript reviews these concepts and present a case study that demonstrates the use of a novel intelligent hybrid algorithms for Industry 4.0 applications with limited data. In particular, an intelligent algorithm is proposed for robust data modeling of nonlinear systems based on input-output data. In our approach, a novel hybrid data-driven combining the Group-Method of Data-Handling and Singular-Value Decomposition is adapted to find an offline deterministic model combined with Pareto multi-objective optimization to overcome the overfitting issue. An Unscented-Kalman-Filter is also incorporated to update the coefficient of the deterministic model and increase its robustness against data uncertainties. The effectiveness of the proposed method is examined on a set of real industrial measurements.
Y1  - 2020
U6  - https://doi.org/10.1109/ACCESS.2020.2999898
SN  - 2169-3536
VL  - 8
IS  - Art. 9108222
SP  - 111381
EP  - 111393
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Maurischat, Andreas
A1  - Perkins, Rudolph
T1  - Taylor coefficients of Anderson generating functions and Drinfeld torsion extensions
N2  - We generalize our work on Carlitz prime power torsion extension to torsion extensions of Drinfeld modules of arbitrary rank. As in the Carlitz case, we give a description of these extensions in terms of evaluations of Anderson generating functions and their hyperderivatives at roots of unity. We also give a direct proof that the image of the Galois representation attached to the p-adic Tate module lies in the p-adic points of the motivic Galois group. This is a generalization of the corresponding result of Chang and Papanikolas for the t-adic case.
Y1  - 2020
U6  - https://doi.org/10.1142/S1793042122500099
IS  - Vol. 18, No. 01
SP  - 113
EP  - 130
PB  - World Scientific
CY  - Singapur
ER  - 
TY  - JOUR
A1  - Neu, Eugen
A1  - Janser, Frank
A1  - Khatibi, Akbar A.
A1  - Orifici, Adrian C.
T1  - Fully Automated Operational Modal Analysis using multi-stage clustering
JF  - Mechanical Systems and Signal Processing
Y1  - 2017
U6  - https://doi.org/10.1016/j.ymssp.2016.07.031
SN  - 0888-3270
VL  - Vol. 84, Part A
SP  - 308
EP  - 323
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Keinz, Jan
A1  - Kusterer, Karsten
A1  - Ayed, Anis Haj
A1  - Kazari, Masahide
A1  - Kitajima, Junichi
A1  - Horikawa, Atsushi
A1  - Okada, Kunio
T1  - Experimental and Numerical Study on Optimizing the Dry Low NOₓ Micromix Hydrogen Combustion Principle for Industrial Gas Turbine Applications
JF  - Journal of Thermal Science and Engineering Applications
N2  - Combined with the use of renewable energy sources for its production, hydrogen represents a possible alternative gas turbine fuel for future low-emission power generation. Due to the difference in the physical properties of hydrogen compared to other fuels such as natural gas, well-established gas turbine combustion systems cannot be directly applied to dry low NOₓ (DLN) hydrogen combustion. The DLN micromix combustion of hydrogen has been under development for many years, since it has the promise to significantly reduce NOₓ emissions. This combustion principle for air-breathing engines is based on crossflow mixing of air and gaseous hydrogen. Air and hydrogen react in multiple miniaturized diffusion-type flames with an inherent safety against flashback and with low NOₓ emissions due to a very short residence time of the reactants in the flame region. The paper presents an advanced DLN micromix hydrogen application. The experimental and numerical study shows a combustor configuration with a significantly reduced number of enlarged fuel injectors with high-thermal power output at constant energy density. Larger fuel injectors reduce manufacturing costs, are more robust and less sensitive to fuel contamination and blockage in industrial environments. The experimental and numerical results confirm the successful application of high-energy injectors, while the DLN micromix characteristics of the design point, under part-load conditions, and under off-design operation are maintained. Atmospheric test rig data on NOₓ emissions, optical flame-structure, and combustor material temperatures are compared to numerical simulations and show good agreement. The impact of the applied scaling and design laws on the miniaturized micromix flamelets is particularly investigated numerically for the resulting flow field, the flame-structure, and NOₓ formation.
Y1  - 2016
U6  - https://doi.org/10.1115/1.4034849
SN  - 1948-5093
N1  - TSEA-15-1227
VL  - 9
IS  - 2
SP  - 021001
EP  - 021001-10
PB  - ASME
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Ayed, Anis Haj
A1  - Kusterer, Karsten
A1  - Funke, Harald
A1  - Keinz, Jan
T1  - CFD Based Improvement of the DLN Hydrogen Micromix Combustion Technology at Increased Energy Densities
JF  - American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS)
N2  - Combined with the use of renewable energy sources for its production, Hydrogen represents a possible alternative gas turbine fuel within future low emission power generation. Due to the large difference in the physical properties of Hydrogen compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for Dry Low NOx (DLN) Hydrogen combustion. Thus, the development of DLN combustion technologies is an essential and challenging task for the future of Hydrogen fuelled gas turbines. The DLN Micromix combustion principle for hydrogen fuel has been developed to significantly reduce NOx-emissions. This combustion principle is based on cross-flow mixing of air and gaseous hydrogen which reacts in multiple miniaturized diffusion-type flames. The major advantages of this combustion principle are the inherent safety against flash-back and the low NOx-emissions due to a very short residence time of reactants in the flame region of the micro-flames. The Micromix Combustion technology has been already proven experimentally and numerically for pure Hydrogen fuel operation at different energy density levels. The aim of the present study is to analyze the influence of different geometry parameter variations on the flame structure and the NOx emission and to identify the most relevant design parameters, aiming to provide a physical understanding of the Micromix flame sensitivity to the burner design and identify further optimization potential of this innovative combustion technology while increasing its energy density and making it mature enough for real gas turbine application. The study reveals great optimization potential of the Micromix Combustion technology with respect to the DLN characteristics and gives insight into the impact of geometry modifications on flame structure and NOx emission. This allows to further increase the energy density of the Micromix burners and to integrate this technology in industrial gas turbines.
Y1  - 2016
SN  - 2313-4402
VL  - 26
IS  - 3
SP  - 290
EP  - 303
PB  - GSSRR
ER  - 
TY  - JOUR
A1  - Neu, Eugen
A1  - Janser, Frank
A1  - Khatibi, Akbar A.
A1  - Orifici, Adrian C.
T1  - Automated modal parameter-based anomaly detection under varying wind excitation
JF  - Structural Health Monitoring
N2  - Wind-induced operational variability is one of the major challenges for structural health monitoring of slender engineering structures like aircraft wings or wind turbine blades. Damage sensitive features often show an even bigger sensitivity to operational variability. In this study a composite cantilever was subjected to multiple mass configurations, velocities and angles of attack in a controlled wind tunnel environment. A small-scale impact damage was introduced to the specimen and the structural response measurements were repeated. The proposed damage detection methodology is based on automated operational modal analysis. A novel baseline preparation procedure is described that reduces the amount of user interaction to the provision of a single consistency threshold. The procedure starts with an indeterminate number of operational modal analysis identifications from a large number of datasets and returns a complete baseline matrix of natural frequencies and damping ratios that is suitable for subsequent anomaly detection. Mahalanobis distance-based anomaly detection is then applied to successfully detect the damage under varying severities of operational variability and with various degrees of knowledge about the present operational conditions. The damage detection capabilities of the proposed methodology were found to be excellent under varying velocities and angles of attack. Damage detection was less successful under joint mass and wind variability but could be significantly improved through the provision of the currently encountered operational conditions.
Y1  - 2016
U6  - https://doi.org/10.1177/1475921716665803
SN  - 1475-9217
VL  - 15
IS  - 6
SP  - 1
EP  - 20
PB  - Sage
CY  - London
ER  - 
TY  - JOUR
A1  - Maurischat, Andreas
T1  - Algebraic independence of the Carlitz period and its hyperderivatives
KW  - Drinfeld modules
KW  - t-modules
KW  - Transcendence
KW  - Hyperdifferentials
Y1  - 2021
N1  - Zweitveröffentlichung.
Verlagsveröffentlichung: https://doi.org/10.1016/j.jnt.2022.01.006
SP  - 1
EP  - 12
ER  -