一种新型活塞杆连接结构及其力学可靠性分析

A New Type of Connecting Structure of Piston Rod and Its Mechanical Reliability Analysis

针对往复压缩机活塞杆与十字头螺纹连接处经常出现疲劳断裂问题，提出一种新型活塞杆螺纹连接结构，并对其进行了相关力学可靠性分析。首先，根据弹性力学理论推导出新型活塞杆螺纹连接结构的应力分布计算式，以及螺纹根部附加弯矩计算式；之后，分别以工作中螺纹根部的应力幅和附件弯矩为失效准则，采用一次可靠性分析法中验算点法来分析新结构的可靠性；最终，通过经典的力学理论和可靠性分析方法，论证新结构在提高活塞杆疲劳强度可靠性方面的优势。

For reciprocating compressor piston rod and cross threaded joints often appear fatigue fracture problems, a new type of pis- ton rod threaded connection structure is put forward, and the related mechanical reliability analysis is carried out in this paper. First of all, based on the theory of elasticity mechanics, the stress distribution calculation formula for the new type of piston rod threaded connection structure and the calculation formula of the additional bending moment and thread root are deduced. Then in order to work in the thread root bending stress amplitude and accessories as the failure criteria respectively, the checking point method in structural reliability analysis is used to analyze the reliability of the new structure. In the end, through the classic mechanics theory and reliability analysis method, the advantages of new structure in improving the piston rod fatigue strength reliability are demonstrated.