Fatigue strength reliability analysis of diesel connecting rod based on stochastic finite element method

摘要

In this paper, stress of a diesel connecting rod (CR) is analyzed by the perturbation stochastic finite element method (PSFEM). A fatigue failure criterion of a diesel CR is also put forward with Corten-Dolan fatigue cumulative damage theory.Based on fatigue failure criterion and the results of stochastic stress analysis, the advanced first order second moment (AFOSM) method is used for fatigue strength reliability analysis. It is shown that PSFEM is efficient and accurate in stochasticstress analysis by comparing with Monte-Carlo simulation. The analysis shows that the reliability of a certain type of diesel CR is 0.99917, which coincides with the statistical data from the factory. It is also found that operating parameters such ascombustion peak pressure and engine rotary speed have the greatest influence on CR reliability because of the large variances and high stress response sensitivity.