In order to solve the problem of difficult theoretical modeling caused by complex threaded contact in the assembly and tightening process of bolted joint structure, a refined modeling method is proposed. Through the assembly torque model, the relationship between tightening torque and preload is obtained. According to the tensile and torsional equilibrium analysis of the bolt during the tightening process, the differential equations of tension and torsion of the bolt are acquired. Combined with the small deformation conditions and boundary conditions of the bolt and nut thread contact points during the tightening process, a complete stress distribution model is obtained. For the analytical model requirement in forward design, the analytical solution for bolt load and deformation distribution is obtained under the small deformation assumption and unchanged initial configuration, and a simplified analytical solution is further deduced. By simulating the stress distribution during tightening process, the screw load and displacement distribution curves under the specified torque are obtained. Comparison reveals that the numerical solution results are highly consistent with the analytical solution, providing a solid theoretical foundation for the forward design of fasteners. 

针对螺栓连接结构在装配拧紧过程中复杂的螺纹接触造成的理论建模困难问题, 提出一个精细化建模方法。通过建立装配扭矩模型, 得出拧紧扭矩与预紧力之间的关系。根据拧紧过程中螺栓拉伸和扭转平衡微元分析, 获得螺栓本体的拉伸和扭转微分方程。结合拧紧过程中螺栓与螺母螺纹接触点的变形协调条件和边界条件, 得到完整的螺栓拧紧应力分布模型。针对正向设计需要解析模型的需求, 基于小变形假设, 在初始构形保持不变的情况下得到螺栓载荷和变形分布的解析解, 并进一步推导获得简化的解析解。通过仿真拧紧过程中的应力分布, 得到指定扭矩下的螺杆载荷和位移分布曲线。通过对比, 数值解结果与解析解高度一致, 可为紧固件的正向设计提供理论基础。