Ultrasonic compaction of granular geological materials

Abstract

It has been shown that the compaction of granular materials for applications such as pharmaceutical tableting and plastic moulding can be enhanced by ultrasonic vibration of the compaction die. Ultrasonic vibrations can reduce the compaction pressure and increase particle fusion, leading to higher strength products. In this paper, the potential benefits of ultrasonics in the compaction of geological granular materials in downhole applications are explored, to gain insight into the effects of ultrasonic vibrations on compaction of different materials commonly encountered in sub-sea drilling. Ultrasonic vibrations are applied, using a resonant 20kHz compactor, to the compaction of loose sand and drill waste cuttings derived from oolitic limestone, clean quartz sandstone, and slate-phyllite. For each material, a higher strain for a given compaction pressure was achieved, with higher sample density compared to that in the case of an absence of ultrasonics. The relationships between the operational parameters of ultrasonic vibration amplitude and true strain rate are explored and shown to be dependent on the physical characteristics of the compacting materials.

Transportation of granular materials with ultrasonic augers

“…The transition is more complex though, because in mayonnaise (a Bingham plastic) this occurs at an absolute yield stress, but in granular media the breakdown (unjamming) is friction based [7], and influenced by pressure and particle shape [8]. It can also, apparently, be triggered by ultrasonic vibration [9].…”

High power ultrasonic effect on soil compaction for different static pressure

“…Many studies have been reported that the powder compaction is improved by decreasing the friction of powder caused by ultrasonic vibration [1][2][3] . Generally, the powder compaction is performed with ultrasonic vibration as well as high static pressure.…”

“…The powder compacting technique using ultrasound has been used in various industrial fields, such as, pharmaceutical, metal metallurgy, and environmental radioactive sample preparation. [1][2][3] Recently, it is known that the compaction assisted with ultrasound in the manufacturing process of tablets has brought into to increase the relative density of tablets by decreasing the porosity in the tablets and it is utilized to increase the drug efficiency per unit volume or the dissolution time of the drug. [4][5][6] Ultrasonic vibration in the powder compacting process is known to reduce the effective friction coefficient of powder.…”