Investigation into failure mechanisms of lunar regolith simulant under thin-walled drilling tool with critical parameters

Abstract

Acquiring pristine deep lunar regolith cores with appropriate drilling tools is crucial for deciphering the lunar geological history. Conventional thick-walled drill bits are inherently limited in obtaining deep lunar regolith samples, whereas thin-walled coring bits offer a promising solution for lunar deep drilling. To support future lunar deep exploration missions, this study systematically investigates the failure mechanisms of lunar regolith induced by thin-walled drilling tools. Firstly, five thin-walled bit configurations were designed and evaluated based on drilling load, coring efficiency, and disturbance minimization, with Bit D demonstrating optimal overall performance. And the interaction mechanisms between differently configured coring bits and large-particle lunar regolith were elucidated. Coring experiments under critical drilling parameters revealed an operational window for the feed-to-rotation ratio (FRR of 2.0–2.5), effectively balancing drilling load and core recovery rate. Furthermore, a novel theoretical framework was developed to characterize dynamic drilling load parameters, supported by experimental validation. Based on these findings, practical strategies are proposed to mitigate drilling-induced disturbances, including parameter optimization and bit structural improvements. This research could provide valuable insights for designing advanced lunar deep drilling tools and developing drilling procedures.