Including bolt bending stiffness in finite‐element analysis of flanged connections

Abstract

SUMMARYThe stiffness matrix of a spring constraint is derived that can restrict only rotation in a mesh of finite elements having no rotation as a degree of freedom. It is connected to two nodes of the structure and does not increase the total number of degrees of freedom. To validate the stiffness matrix, a simple 2-D numerical example is presented which is in excellent agreement with theoretical results.Integral grey cast iron flanges (BS4504: 1969) are analysed including and not including the bending stiffness of the bolts. The analysis shows that neglecting the bending stiffness of the bolts results in up to 35% error of overestimating the maximum stress in large-diameter flanges.