Finite-Discrete Element Modeling of Impacts Experiments on Mars Regolith Proxies
Session: InSight Seismology on Mars: Results From the First (Earth) Year of Data and Prospects for the Future [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description:
InSight landed on Mars on November 26, 2018 and has since placed the seismometer SEIS on the surface of the planet (Banfield et al., 2019; Lognonné et al., 2019). Among the scientific objectives of the mission are a new seismic model of Mars based on data and a refined estimate of the meteorite flow. Both objectives will benefit from a better capability to identify and exploit seismic signals produced by impacts. Here, we propose a model of generation of seismic waves by impacts using numerical methods.
Our model is developed specifically for Mars regolith, the surface layer of unconsolidated rocky material covering the bedrock (Morgan et al., 2018). The impact process for small and more frequent impactors takes places mostly within it. Regolith is a granular material, for which high-fidelity modeling of seismic waves produced by shocks is challenging due to its complex, non-linear response.
We show modeling results using the Hybrid Optimization Software Suite (HOSS) mechanical simulation software developed at Los Alamos National Laboratory. HOSS is a Lagrangian code, based on the combined Finite-Discrete Element Methodology (FDEM) for an efficient description of both continuum and discontinuum dynamics (Munjiza et al., 2014). We have conducted a parametric study to analyze the sensitivity of the simulation results to key parameters defining the equation of state and strength equation of the target material. These key parameters are identified and fixed to match results from a set of small-scale impact experiments on pumice sand (Richardson & Kedar, 2013) conducted at the NASA Ames Vertical Gun Range facility.
The novel numerical model developed here comes to agreement with experimental data in terms of amplitude and wave shape. More work is needed in order to model the signal on the shallow accelerometers of this experiment, which are the most relevant to the InSight mission as SEIS is a surface receptor. (LA-UR-20-20347)
Presenting Author: Marouchka Froment
Authors
Marouchka Froment marouchka.froment@ens-paris-saclay.fr Los Alamos National Laboratory, Los Alamos, New Mexico, United States Presenting Author
Corresponding Author
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Esteban Rougier erougier@lanl.gov Los Alamos National Laboratory, Los Alamos, New Mexico, United States |
Carene Larmat carene@lanl.gov Los Alamos National Laboratory, Los Alamos, New Mexico, United States |
Zhou Lei zlei@lanl.gov Los Alamos National Laboratory, Los Alamos, New Mexico, United States |
Bryan J Euser beuser@lanl.gov Los Alamos National Laboratory, Los Alamos, New Mexico, United States |
Sharon Kedar sharon.kedar@jpl.nasa.gov Jet Propulsion Laboratory, Caltech, Pasadena, California, United States |
James E Richardson jerichardsonjr@psi.edu Planetary Science Institute, Tucson, Arizona, United States |
Taichi Kawamura kawamura@ipgp.fr Institut de Physique du Globe de Paris, Paris, , France |
Philippe Lognonné lognonne@ipgp.fr Institut de Physique du Globe de Paris, Paris, , France |
Finite-Discrete Element Modeling of Impacts Experiments on Mars Regolith Proxies
Category
Insight Seismology on Mars: Results From the First (Earth) Year of Data and Prospects for the Future