内燃机曲轴裂纹故障的动态监测方法研究

Research on Monitoring the Crack in Crankshaft of I.C E

采用振动分析法研究了诊断曲轴裂纹的途径。根据曲轴内拐角处裂纹的特点,结合断裂力学中的理论———可以从应变能密度方程出发计算得出因裂纹而引起的局部柔度变化,提出了一种推演含有斜向裂纹矩形截面梁单元刚度矩阵的新方法。应用此裂纹梁单元,采用有限元法模拟,可以计算出含有裂纹的单缸发动机曲轴的非线性振动响应。通过分析计算结果,得出了一些有益于诊断曲轴裂纹的结论。

Crack detection of cracked crankshaft was researched through vibration analysis. According to the characteristics of the crack occurred in inside corner of crankshaft, the additional flexibility that the crack generates in its vicinity was evaluated by using the strain energy density function given by linear fracture mechanics theory. A new cracked finite element stiffness matrix is deduced. Based on this cracked beam element, the nonlinear dynamic response of a cracked crankshaft was analyzed by FEM. Some useful conclusions for diagnosing cracked crankshaft systems was proposed.