Investigation of energy storage in bolted joint components and the development of a geometry selection design tool for Belleville washers

摘要

Despite the advantages and widespread use of bolted joints in manufacturing, one major problem is their tendency to loosen, which can ultimately cause the joint to fail. This research evaluates strain energy storage in the Belleville washer, to determine how the washer's design could be modified to counteract relaxation in the bolt, which causes loosening. Finite Element Analysis (FEA) is used to study the strain energy, bolt preload, deflections, and other parameters of various geometric configurations of Belleville washers and shows that the strain energy is not optimally utilized with conventional Belleville washers, which have constant wall thickness. Tapering the Belleville washer reduces its weight significantly, thereby increasing the washer's energy storage capacity. The FEA data are used to develop a tool for helping to design Belleville washer geometry that can prevent bolt loosening. One of the tool's inputs is the bolt deflection relaxation within the acceptable bolt preload window. This work opens further research avenues for analyzing anti-loosening joints from the perspective of the elastic energy stored in the joint and thereby predicting when the joint might fail.