STUDY OF THE IMPACT CRATERING PROCESS BY MEANS OF NON-DESTRUCTIVE TESTING TECHNIQUES ON A MODEL SPECIMEN

There is need for a detailed investigation of the dynamic rock failure due to hypervelocity impact and for a better understanding of body-body collisions that are one of the most common physical processes of our solar system. These processes are studied in a project on a much smaller scale at dry and wet sandstone targets using a light-gas gun accelerator at the Fraunhofer-Institute for High-Speed Dynamics (Ernst-Mach-Institute, EMI) in Freiburg, Germany.

Nondestructive testing techniques are a proper tool to investigate the damage and the fracture zone beneath experimentally produced craters three-dimensionally and with high spatial resolution. Methods based on ultrasound and acoustic emission techniques are developed and applied to detect inhomogeneities and cracks to characterize a target before, during and after impact. The fracturing underneath the crater following the impact is for example observed by the recording of the aftershocks in form of acoustic emissions. The characterization of the target before and after impact is done using ultrasound tomography. Preliminary results of the measurements are given.