Study on the Looseness Caused by Local Slip and Load Bearing Capacity of Threaded Connections Under Transverse Cyclic Loading

Abstract Under transverse cyclic loading, slip will occur on the contact surfaces in a threaded connection, causing rotational loosening of the connection. It is necessary to detect and analyze the loosening behavior of threaded connections caused by slippage. In this article, a self-driven sensor based on the principles of triboelectric nanogenerators (TENGs) was used to monitor the rotational looseness of a tight threaded stud connection subjected to transverse cyclic loads. The finite element simulation was conducted on the contact slip in the stud connection in the experiment under transverse cyclic loading to reveal the loosening phenomenon of threaded connections caused by local slip propagation with the increase of load cycles. Under a certain preload, only when the amplitude of the lateral cyclic load does not exceed a critical value, will the thread contact surface not experience local slip propagation. Therefore, a local slip influence coefficient was proposed for calculating the critical transverse cyclic load amplitude, and its influencing factors were discussed. This study provides a new approach to the anti-loosening design of threaded connections.