Direct measurement and theoretical prediction model of interparticle adhesion force between irregular planetary regolith particles

Abstract

Interparticle adhesion force has a controlling effect on the physical and mechanical properties of planetary regolith and rocks. The current research on the adhesion force of planetary regolith and rock particles has been primarily based on the assumption of smooth spherical particles to calculate the intergranular adhesion force; this approach lacks consideration for the adhesion force between irregular shaped particles. In our study, an innovative approach was established to directly measure the adhesion force between the arbitrary irregular shaped particles; the probe was modified using simulated lunar soil particles that were a typical representation of planetary regolith. The experimental results showed that for irregular shaped mineral particles, the particle size and mineral composition had no significant influence on the interparticle adhesion force; however, the complex morphology of the contact surface predominantly controlled the adhesion force. As the contact surface roughness increased, the adhesion force gradually decreased, and the rate of decrease gradually slowed; these results were consistent with the change trend predicted via the theoretical models of quantum electrodynamics. Moreover, a theoretical model to predict the adhesion force between the irregular shaped particles was constructed based on Rabinovich’s theory, and the prediction results were correlated with the experimental measurements.