考虑装配间隙的双搭接螺栓连接剪切刚度的解析求解方法

The joint stiffness is an important parameter in the design of composite bolted joints and is influenced largely by the bolt-hole clearance. Aiming at the elastic foundation stiffness k_c ^*, an analytical expression was derived by introducing Liu Cai-Shan's inner cylindrical contact model. This analytical expression can take account of the bolt-hole clearance and it shows that k_c ^* deceases with the increase of clearance. Aiming at the nail-head restraint coefficient k_r, an approximate expression was obtained by the strain energy method from a reasonable stress distribution hypothesis. Based on k_c ^* and k_r, the analytical solution of the joint stiffness was derived from an elastic foundation beam model. The load-displacement curves of double-lap bolted joints predicted by the analytical method were validated by 3-D detailed FE-models. Finally, the mechanical mechanism of the clearance influence on the joint stiffness was analyzed by finite element method. Moreover, the influences of the clearances form 1-300 μm were given quantitatively by the analytic method.