Estimation method for inadequate fatigue test result of structures with multi-similar-details

A method for estimating fatigue life distribution parameters with inadequate result obtained by fatigue test of structures with multi-similar-details was proposed. Based on the assumption that fatigue life follows the log-normal distribution and 2-parameter Weibull distribution respectively, the relationship of two kinds of distribution parameters, one was adopted to describe the single detail fatigue quality and the other was gained by inadequate test results of multi-similar-detail structures, was discussed. The analysis indicates that there is a significantly difference between the two kinds of parameters, however a determinate function of the amount of details can be obtained to describe this relationship. The way of estimating single detail fatigue distribution parameters via inadequate data was presented. Numerical simulations were conducted to analysis the effects of number of specimens and the amount of details on the estimating results, which shows that when the amount of details is not very large, it is the number of specimens, but not the amount of details, which has great effect on the dispersivity of parameter estimation.