往复式压缩机连杆的疲劳及裂纹扩展研究

The fatigue and crack growth investigation of reciprocating compressor connecting rods

为了研究往复式压缩机连杆在交变载荷作用下的裂纹扩展问题,本文进行了连杆的有限元静强度分析,研究了连杆表面粗糙度对连杆疲劳性能的影响规律。计算结果表明:应力集中和最大Mises应力出现在连杆大头盖外圆面和螺栓台面的过渡区;在表面粗糙度从1mm~75mm的变化范围内,连杆最小疲劳安全系数由1.728降到1.465;连杆大头盖外圆面和螺栓台面的过渡区是连杆疲劳安全系数最小的区域。在此基础上,对连杆大头盖外圆面和螺栓台面过渡区的裂纹扩展进行了模拟计算。结果表明,连杆大头盖外圆面和螺栓台面的过渡区的裂纹长度扩展到5.1mm时,连杆的疲劳裂纹寿命为7.1×10^(4)次。

In order to investigate the fatigue and crack growth of reciprocating compressor connecting rods under alternating loads,the finite element analysis is performed,and the surface roughness influence of the connecting rod on the fatigue performance of the connecting rod is studied.Numerical results demonstrate that the stress concentration and the maximum Mises stress appear in the transition area between the outer circular surface of the connecting rod head and the bolt table surface.Additionally,the minimum fatigue safety factor of the connecting rod decreases from 1.728 to 1.465 when the surface roughness varies from 1μm to 75μm.The transition area between the outer circle surface of the connecting rod cap and the bolt table surface is the area with the smallest fatigue safety coefficient.Finally,the crack propagation simulation calculation is performed in this transition area,based on which the crack propagation is analyzed and the fatigue crack life of the connecting rod is predicted.