Evolution, Mechanism and Intelligent Application of Percussion-Based Monitoring Technology for Bolt Looseness in Engineering Structures

This study provides a review of recent advances in percussion-based bolt looseness monitoring. Beginning with the engineering mechanism of the tap-induced vibro-acoustic response in bolted joints, this study traces the technical evolution of the field across three progressive levels: basic signal preprocessing, discriminative feature extraction, and intelligent diagnosis modeling. Subsequently, a multi-dimensional comparative analysis of typical monitoring methods is conducted, and targeted combined detection schemes tailored to different engineering scenarios are synthesized. Furthermore, the main constraints impeding engineering application are elucidated, and prospective research directions oriented to complex engineering conditions are outlined. This review is intended to provide a systematic technical roadmap and theoretical framework for the further development and engineering deployment of intelligent percussion-based bolt looseness monitoring technology.