Project 5

Numerical modeling of impact cratering processes

Project directors:

Kai Wünnemann, Museum für Naturkunde Berlin (MfN)
Stefan Hiermaier, Ernst-Mach Institut für Kurzzeitdynamik Freiburg, Fraunhofer-Institut (EMI)

Research staff:

Nicole Güldemeister (PhD student, MfN)
Nathanael Durr (PhD student, EMI)

Summary

The use of computer codes to model and predict the collision of cosmic bodies, so-called hydrocodes, has become widespread, and the codes have grown in sophis¬tication over the last 30 years. Comprehensive understanding of the dynamic processes during an impact event can only be reached by combining geologic and geophysical observations, and experimental studies with numerical modeling. Numerical codes are based on the fundamental principles of continuum mechanics and material models that describe the behavior of geo-materials under extreme pressures, temperatures and shear stresses occuring during crater formation and shock wave compression.

Currently available codes use simplified material models that do not account for specific material properties, such as porosity and water content, that are typical for planetary surfaces (sedimentary rocks on Earth, regolith breccia for example on Mars or Moon, comets) and have a huge effect on the impact process. This project aims at the development of new material models for use in hydrocodes that are capable to treat the behavior of porous dry or water-saturated rocks much more realistically. The new models will be tested against cratering experiments in terms of shape and size of the resulting crater, fracturing and shock wave modifications in the traget rocks, and geophysically detectable changes in rocks (electrical conductivity, elastic wave velocities). Finally the models will be applied to the dimensions of natural craters on planetary surfaces considering the scale dependency of material properties such as strength and brittle/ductile deformation.

Results

You can find the results here.