Covering Shock Waves on Mars induced by INSIGHTS's HP3-Mole - Efficient Co-Simulation using DEM and Multi-Domain Dynamics

Abstract

NASAs discovery mission InSight (Interior Seismic Investigations, Geodesy and Heat Transport) scheduled for launch in 2018 will investigate the interior of Mars. For the subsurface locomotion, DLR's self-impelling nail nicknamed the "Mole" needs to hammer itself down to 5m into the martian soil with less than 5W of input power. A major focus during the Mole's development has been on simulation and analysis using virtual prototypes. As certain aspects of the environmental conditions on Mars cannot be recreated and tested on earth, high-�delity coupled simulations are required to achieve the accuracy needed. These co-simulations are composed by a multi-body based cross domain model for the hammering device and a discrete element model for the soil. The article focuses on the coupling strategy of both models as well solutions in terms of communication. Furthermore e�ciency improvements of the computationally expensive DEM models will be presented. Using these approaches the detailed stroke cycle and shock wave propagation are analyzed. Allowing to evaluate the performance under martian or terrestrial conditions.