Current finite element (FE) simulating methods for pre-tightening process of thread fasteners have some shortcomings. In order to ensure the accuracy and efficiency simultaneously, the interference fit method and the direct torsion method are combined via ANSYS APDL to form a new pre-tightening means. Firstly, FE models of the thread pair structure before and after simulating the necking plastic forming process are obtained. Further assembly process simulation of the necking anti-loosening nuts is realized. Via different pre-tightening methods for simulating the assembly process, the thread pair load distribution, the contact stress state and the torsion-tension relationship can be obtained. Via comparing the numerical results of the zero closure amount nuts with some theoretical solutions, the reliabilities of the FE models and the simulation process are verified. Furthermore, the calculation time and numerical results of different pre-tightening methods are compared to prove the combined pre-tightening method is reliable and effective. 

针对目前有限元仿真手段在螺纹紧固件预紧过程研究中的不足, 借助ANSYS的APDL, 将过盈配合法与直接扭转法相结合, 提出一种能够保证计算精度的高效预紧手段。首先通过模拟收口塑性成型过程, 获得收口加工前后的螺纹副结构有限元模型, 继而实现收口防松螺母的装配过程仿真。利用不同的预紧手段模拟装配过程, 获得螺纹副承载分布、接触应力状态和扭拉关系。通过对比未收口螺母的数值解与理论解, 验证所建模型以及仿真过程的可靠性。通过对比不同预紧手段的计算时间和数值结果, 证明联合预紧手段是可靠而有效的。