Prediction Method of Tightening Characteristic of the Bolted Joints considering Surface Roughness of Parts

Abstract

In case of determining tightening specifications of the bolted joints, it is important to understand the relationships between the rotation angles and axial forces in the joint tightening process. Also, it is efficient to predict accurately the relationship. As the prediction method, the simplified calculation formula is shown in JIS B 1083. However, it was shown that there is a margin of error on the relationship between the prediction results and physical test results. And it is thought the reason is that geometrical details of bolted joints and approaches of interface caused by surface roughness of each part are not considered. In this study, the simplified calculation, FEM analyses and experiments are conducted, and those results of the relationships between the rotation angles and axial forces are compared. Influence of the geometrical detail shape and approaches of interface are investigated. Considering both of detail shape and approaches of interface, it is shown the relationships between the rotation angles and axial forces of actual bolted joints are predicted.