Study of Three-Dimensional Stress Distribution and Damage Characterization of Bolt Composite Joint

Abstract

A 3D finite element model of bolt composite joint has been established to determine the stress distribution on the contact surface. The effects of clamping torque and friction on the contact stress and interlaminar normal stress are considered. From the analysis results, contact stress is bared mainly by the 0° layer. The distribution and magnitude of contact stress are conducted by friction. The effect of clamping torque on interlaminar normal stress is very strong. A 3D damage user subroutine is added to the FEM to simulate the damage of joint. By the means of damage simulation, the initiation and progression direction of three types damage are predicted. Matrix cracking and fiber-matrix shear occur at first, and fiber buckling is founded subsequently. The matrix cracking and fiber-matrix debonding initiate at circumferential angle 45°and 135°, and fiber buckling initiate at the 0° layer on the bearing plane. The friction and bolt clamping torque can restrain damage initiation and development.