Study on Prediction Method of Structural Three-parameter Power Function P-S-N Curve

Abstract

This paper applies weighted least square method to estimate the three-parameter power function equation of the fatigue life curve, and uses comprehensive fatigue life coefficient to correct the equation, and at the same time combines probability statistics method to bring out the prediction method of structure's three-parameter power function P-S-N curve, finally applies the prediction method to a ship's frame-type elevate, based on the fatigue test data of it's material-5A06 aluminium alloy, to obtain it's structure's three-parameter power function P-S-N curve. Compared with the conventional least square method, the presented method can give a rational estimation due to it's a best linear unbiased estimator, and this method has stronger practicality in engineering, and can be used in many structures of different materials, for achieving their three-parameter power function P-S-N curve.