Bolt Load Calculation for Hybrid Joint Considering Friction and Nonlinear Stiffness under Combined Thermal and Mechanical Loads

An improved analytical method for calculating the bolt load distribution in single-lap or double-lap multi-bolt composite-metal joint structure considering material nonlinear behaviour and thermal stress is proposed in this paper. The analytical method is based on the stiffness method and the composite material mechanics. The bolt load ratios calculation results of a three-bolt joint structures by the improved method is compared with the results from finite element (FE) method and the relative error less than 7%. The great agreement verifies the accuracy of the analytical method. Besides, this improved has more considering factors and higher accuracy than traditional stiffness method and less calculating cost than FE method.