Ultrasonic Penetration of Granular Materials in Varying Gravity

Abstract

This paper describes the effects of ultrasonically-assisted penetration of granular materials, in high gravity situations. The experimental rig, instrumented to obtain penetration force, rate and power both with and without ultrasonic assistance, was used to drive a penetrator into a granular material inside the ESA Large Diameter Centrifuge at accelerations of up to 10 g during early September 2015. Ultrasonic penetration proved to be most beneficial at lower levels of accelerations, reducing the required overhead weight by 80%, and the total power consumption by 27%.

An experimental study of ultrasonic vibration and the penetration of granular material

“…The experiments at the LDC were focused on mild levels of hypergravity, in order to better extrapolate trends for below 1 g [ 28 ]. To maximize experimental time, only BP was used for these experiments, and the ultrasonic amplitude range was further decreased to 0–1.6 µm.…”

“…The power measurement experiments were repeated in higher gravities using the gravity rig, where total power consumption was shown to reduce consistently at higher gravities, with a maximum value of 27% reduction obtained [ 28 ].…”