• Scheeres, Daniel J.
• Sanchez, Paul
• Sautel, Jeremy

Abstract

Small granular asteroids, due to their size, mass and rotation, have gravitational fields in the order of milli- to micro-g with respect to Earth's gravity. Grain-grain cohesive forces on the other hand, do not escale with asteroid size and thus the cohesive forces between different particles forming an asteroid play a non-negligible role, which can be quantified by the cohesive strength of the medium. Moreover, the size distribution of these particles can be quite wide and this will also have an influence on the cohesive strength. One simple way to measure cohesive strengths is the direct shear test, which is well-known method in Soil Mechanics. In order to precisely control the investigated size distributions we have chosen to use a simulation code that implements a numerical method for the simulation of granular media in this study. We found that in general, cohesive strength scales proportionally with the strength of the cohesive bonds. When large particles are embedded in the medium, the cohesive strength remains steady as long as failure happens through the region of the medium that is formed by the smaller particles. Then, if the volume fraction occupied by the large particles becomes greater than 50%, the cohesive strength of the medium decreases. These results, along with a theoretical interpretation, further numerical tests and their implications for the structural strength of asteroids will be discussed during the conference....

Topics

• impedance spectroscopy
• grain
• simulation
• strength
• shear test
• forming