As the strain fatigue data scatter in lgΔεe-lgN or lgΔεp-lgN coordinates

and their standard deviation increases with reducing of elasticity and plasticity components

ε-N and P-ε-N curves cannot be obtained by group experiment method and homoscedasticity regression analysis method.The mean value method and Wissching method are commonly used in engineering.But they are both approximation methods with significant error.Therefore

an integral inference method for ε-N and P-ε-N curves is presented based on the heteroscedasticity regression analysis theory.It can analyze scattered and heteroscedastic data through treating all the experiment data in different strain levels as an integration.Compared with traditional methods

the presented method can not only save specimens

but also increase precision in ε-N and P-ε-N curve tests effectively.