不同加工方式影响的表面疲劳寿命研究

Study of Surface Fatigue Life Influenced by Different Manufacturing Methods

离心压缩机是工业生产中重要的能量转化装置,针对其在实际生产中常常发生因叶轮疲劳破坏而导致的生产事故的问题,有必要对叶轮表面及内部损伤产生的疲劳裂纹进行研究,以确定叶轮的剩余寿命等具体的疲劳断裂性能。利用损伤力学的方法确立叶轮应力危险区域的裂纹萌生寿命模型并对萌生寿命公式进行推导,并考虑到叶轮加工表面粗糙度对叶轮应力以及裂纹萌生寿命的影响,对模型进行进一步的修正和完善,最终通过了Ansys软件的验证。结果发现模型公式推导出的裂纹萌生寿命与实际生产中叶轮的疲劳寿命相吻合,同时发现不同的加工方式对粗糙度以及叶轮的疲劳寿命的影响非常大,磨削加工叶片的疲劳寿命可以达到普通铣削加工叶片疲劳寿命的30倍以上。

Centrifugal compressor is an important energy conversion device in the industrial production. While in actual production, fatigue damage of the impeller always causes production accidents. So we must analyze fatigue cracks in and on the impeller to determine the impeller＇s performance of fatigue fracture such as residual life, so as to avoid the production accidents. In this paper, the crack initiation life model and the initiation life formula of the impeller＇s dangerous zone are established by using the method of damage mechanics. The material parameters of the impeller is determined according to the experimental data, at the same time considering the surface roughness of the impeller＇s influence on the machining stress and crack initiation life, the model is further improved and revised and finally the Ansys software is verified. It is found that the crack initiation life deduced by the model formula coincides with the fatigue life of the impeller in actual production, and different manufacturing methods lead to different roughness and fatigue life of the impeller, and the fatigue life of the blade can reach more than 30 times of the fatigue life of ordinary milling blades.