螺栓的连接刚度是复合材料连接设计中的重要参数,装配间隙对其有明显的影响.针对弹性基刚度k*c,引入 Liu Cai-Shan的内圆接触模型,推导了考虑装配间隙的解析表达式,发现k*c随着装配间隙增加而降低.针对钉头约束系数kr,基于应力假设和应变能方法,给出了估算表达式.在获得k*c和kr基础上,建立弹性基剪切梁模型并推导了双搭接螺栓连接刚度的解析解,并采用3-D细节有限元模型对解析方法进行了验证.最后,通过有限元方法分析了间隙对连接刚度产生影响的力学机制,并用解析方法定量给出了1~300μm的装配间隙对连接刚度影响的大小.%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*cdeceases with the increase of clearance.Aiming at the nail-head restraint coefficient kr,an approximate expression was obtained by the strain energy method from a reasonable stress distri-bution hypothesis.Based on k*cand kr,the analytical solution of the joint stiffness was derived from an elastic foun-dation 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 stiff-ness was analyzed by finite element method.Moreover,the influences of the clearances form 1-300 μm were given quantitatively by the analytic method.
展开▼
