Strength design system of bolted joints using 3D-FE analysis

(Development of single-body bolt/nut model with equivalent axial and flexural stiffnesses)

Abstract

This study aims to develop a single-body (solid) bolt/nut model utilized in the strength design of bolted joints by using 3D-FE analysis. The model should have the same axial and flexural stiffnesses as the actual bolt/nut assembly. To achieve this, the shank diameter for free-threaded length and the shape of the slits representing mating threads in the single-body bolt/nut model are taken as parameters under axial force and bending moment loadings. The validity of the model was confirmed from the fact that axial stresses acting on the body of the single-body bolt/nut model in cylinder cover bolted joint show good agreement with those obtained experimentally from the measurements by the strain gages put on the bolt shank.