基于线弹性断裂力学,采用有限元分析,对乳化液泵用阀座拉升器中疲劳裂纹扩展进行预测,获得Ⅰ+Ⅱ型(张开型+滑开型)混合型裂纹的等效应力强度因子,并应用到Paris公式中,从而求得裂纹扩展增量以及总的裂纹长度;混合型裂纹扩展方向角也可应用Ⅰ型(张开型)和Ⅱ型(滑开型)的裂纹应力强度因子计算得出。分析表明:在裂纹扩展前期,有限元裂纹扩展方向角约与拉升器螺杆轴线成45°的方向,与试验结果吻合度较高。

Based on the linear elasticity fracture mechanics, the finite element analysis was applied to predict the fatigue crack expansion of the lifter in the valve s eat of emulsion pump.A I + I mode (open type+slip type) equivalent stress strength factor of the mixed type cracks was obtained and was applied to a Paris formula, t hus the crack expansion value and the total crack length was calculated and obtained.The mixed type crack expansion orientation angle also could be calculated with I type (open type) and I type (slip type) crack stress strength factor.The analysis showed that before the crack expanded, the finite element crack expansion orientati on angle would be 45° to the spiral shaft of the lifter and would be high fitted with the experiment results.