Finite Element Analysis on Fatigue Crack Expansion of Lifter in Valve Seat of Emulsion Pump

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.