FRICTIONAL SHEAR TEST OF GRANULAR MEDIA IN PSEUDO LOW-GRAVITY FIELD USING A MAGNETIC DEVICE

摘要

The rational treatment of the frictional interaction between lunar soil and a mechanical system is one of the several technical issues encountered during lunar operations. Therefore, it has become essential to come up with a method to evaluate frictional interaction on lunar surface environment, which is characterized by soft ground, low gravity, and high vacuum. In this study, first a test apparatus was developed to perform the rotational shear test of granular media. Then, a magnetic field device was combined with the friction test apparatus to investigate the effect of gravity on frictional interaction. Using the developed test apparatus, the test was performed under a pseudo low-gravity condition. This enabled the investigation of variations in frictional torque between the granular media and various solid surfaces, with respect to the time elapsed, under the pseudo low-gravity conditions, in which the gravity was adjusted to 1.0 G, 0.95 G, and 0.9 G.