A Parametric Lifetime Model for the Prediction of High-Cycle Fatigue Based on Stress Level and Amplitude

摘要

The goal of this paper is to present a general parametric lifetime model for predicting fatigue behaviour at any stress level and amplitude (for example, at any combination of sigma_(max) and sigma_(min) pair) in the high-cycle fatigue regime. The problem of the design of the experimental laboratory test required for such a prediction is dealt with. The surprising and relevant result is that running two groups of tests for two different constant stress levels of sigma_(max) or sigma_(min) is sufficient to predict the whole collection of Wohler fields for any possible stress level. However, some combinations of tests, such as one for a fixed value of sigma_(max) and one for a fixed value of sigma_(min), are shown to be insufficient. Closed formulas for obtaining any Wohler field from the results of the experiments corresponding to the two different fixed values of sigma_(max) or sigma_(min) are given. Together the proposed model and lab tests allow any fatigue analysis to be performed in the current investigation. One example of application illustrates the proposed method.