TY  - CHAP
A1  - Möhren, Felix
A1  - Bergmann, Ole
A1  - Janser, Frank
A1  - Braun, Carsten
T1  - On the determination of harmonic propeller loads
T2  - AIAA SCITECH 2023 Forum
N2  - Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.
Y1  - 2023
U6  - https://doi.org/10.2514/6.2023-2404
N1  - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, Md & Online
PB  - AIAA
ER  - 
TY  - CHAP
A1  - Baader, Fabian
A1  - Reiswich, M.
A1  - Bartsch, M.
A1  - Keller, D.
A1  - Tiede, E.
A1  - Keck, G.
A1  - Demircian, A.
A1  - Friedrich, M.
A1  - Dachwald, Bernd
A1  - Schüller, K.
A1  - Lehmann, Raphael
A1  - Chojetzki, R.
A1  - Durand, C.
A1  - Rapp, L.
A1  - Kowalski, Julia
A1  - Förstner, R.
T1  - VIPER - Student research on extraterrestrical ice penetration technology
T2  - Proceedings of the 2nd Symposium on Space Educational Activities
N2  - 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.
Y1  - 2018
SP  - 1
EP  - 6
ER  - 
TY  - CHAP
A1  - Grundmann, Jan Thimo
A1  - Bauer, Waldemar
A1  - Borchers, Kai
A1  - Dumont, Etienne
A1  - Grimm, Christian D.
A1  - Ho, Tra-Mi
A1  - Jahnke, Rico
A1  - Koch, Aaron D.
A1  - Lange, Caroline
A1  - Maiwald, Volker
A1  - Meß, Jan-Gerd
A1  - Mikulz, Eugen
A1  - Quantius, Dominik
A1  - Reershemius, Siebo
A1  - Renger, Thomas
A1  - Sasaki, Kaname
A1  - Seefeldt, Patric
A1  - Spietz, Peter
A1  - Spröwitz, Tom
A1  - Sznajder, Maciej
A1  - Toth, Norbert
A1  - Ceriotti, Matteo
A1  - McInnes, Colin
A1  - Peloni, Alessandro
A1  - Biele, Jens
A1  - Krause, Christian
A1  - Dachwald, Bernd
A1  - Hercik, David
A1  - Lichtenheldt, Roy
A1  - Wolff, Friederike
A1  - Koncz, Alexander
A1  - Pelivan, Ivanka
A1  - Schmitz, Nicole
A1  - Boden, Ralf
A1  - Riemann, Johannes
A1  - Seboldt, Wolfgang
A1  - Wejmo, Elisabet
A1  - Ziach, Christian
A1  - Mikschl, Tobias
A1  - Montenegro, Sergio
A1  - Ruffer, Michael
A1  - Cordero, Federico
A1  - Tardivel, Simon
T1  - Solar sails for planetary defense & high-energy missions
T2  - IEEE Aerospace Conference Proceedings
N2  - 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.
Y1  - 2019
U6  - https://doi.org/10.1109/AERO.2019.8741900
N1  - AERO 2019; Big Sky; United States; 2 March 2019 through 9 March 2019
SP  - 1
EP  - 21
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
A1  - Digel, Ilya
A1  - Artmann, Gerhard
T1  - Development and testing of a subsurface probe for detection of life in deep ice : [abstract]
N2  - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth).
KW  - Eisschicht
KW  - Sonde
KW  - subsurface probe
KW  - subsurface ice research
Y1  - 2011
ER  - 
TY  - CHAP
A1  - Duprat, J.
A1  - Dachwald, Bernd
A1  - Hilchenbach, M.
A1  - Engrand, Cecile
A1  - Espe, C.
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Görög, Mark
A1  - Lüsing, N.
A1  - Langenhorst, Falko
T1  - The MARVIN project: a micrometeorite harvester in Antarctic snow
T2  - 44th Lunar and Planetary Science Conference
N2  - MARVIN is an automated drilling and melting probe dedicated to collect pristine interplanetary dust particles (micrometeorites) from central Antarctica snow.
Y1  - 2013
N1  - 44th Lunar and Planetary Science Conference, March 18-22, 2013, The Woodlands, Texas
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Mikucki, Jill A.
A1  - Tulaczyk, Slawek
A1  - Digel, Ilya
A1  - Feldmann, Marco
A1  - Espe, Clemens
A1  - Plescher, Engelbert
A1  - Xu, Changsheng
T1  - IceMole - a maneuverable probe for clean in-situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems : extended abstract / SCAR Open Science Conference 2012, Session 29: Advancing Clean Technologies for Exploration of Glacial Aquatic Ecosystems
N2  - The ”IceMole“ is a novel maneuverable subsurface ice probe for clean in-situ analysis and sampling of subsurface ice and subglacial water/brine. It is developed and build at FH Aachen University of Applied Sciences’ Astronautical Laboratory. A first prototype was successfully tested on the Swiss Morteratsch glacier in 2010. Clean sampling is achieved with a hollow ice screw (as it is used in mountaineering) at the tip of the probe. Maneuverability is achieved with a differentially heated melting head. Funded by the German Space Agency (DLR), a consortium led by FH Aachen currently develops a much more advanced IceMole probe, which includes a sophisticated system for obstacle avoidance, target detection, and navigation in the ice. We intend to use this probe for taking clean samples of subglacial brine at the Blood Falls (McMurdo Dry Valleys, East Antarctica) for chemical and microbiological analysis. In our conference contribution, we 1) describe the IceMole design, 2) report the results of the field tests of the first prototype on the Morteratsch glacier, 3) discuss the probe’s potential for the clean in-situ analysis and sampling of subsurface ice and subglacial liquids, and 4) outline the way ahead in the development of this technology.
KW  - Eisschicht
KW  - Sonde
KW  - subsurface ice
KW  - subglacial aquatic ecosystems
Y1  - 2012
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
T1  - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier
T2  - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011
N2  - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth).
Y1  - 2011
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Feldmann, Marco
A1  - Espe, Clemens
A1  - Plescher, Engelbert
A1  - Konstantinidis, K.
A1  - Forstner, R.
T1  - Enceladus explorer - A maneuverable subsurface probe for autonomous navigation through deep ice
T2  - 63rd International Astronautical Congress 2012, IAC 2012; Naples; Italy; 1 October 2012 through 5 October 2012. (Proceedings of the International Astronautical Congress, IAC ; 3)
Y1  - 2012
SN  - 978-1-62276-979-7
SP  - 1756
EP  - 1766
PB  - Curran
CY  - Red Hook, NY
ER  -