Comparison of Material Fatigue Testing Strategies regarding Failure-Free Load Level of Steel Specimens using Bootstrapping and Statistical Models

Abstract

The analysis of material fatigue data is an important step in the development of complex technical products to achieve a design which reliably withstands field load but avoids over-engineered and further unnecessary weight, energy consumption, and consequently, life cycle costs. The application of statistical methods helps to consider both, the variability of real-world load situations and the variability of material load capacity. However, to provide effective and accurate results, not only analysis methods but also data generation techniques should be selected with care. In this paper, we compare several material fatigue evaluation strategies, all consisting of a data generation/test part and an analysis part. E.g., stair-case, load-step and pearl-string as test procedures and Dixon-Mood analysis, lifetime-stress regression or the random fatigue limit model as analysis methods are investigated. The sensitivity on parameters which have to be set and the accuracy regarding load capacity as well as the required testing effort are compared. Load-step provides the most accurate estimation of the failure-free load level but is the most expensive method. Pearl-string and DoE provide similar results with much less effort and moderately higher uncertainty compared to load-step.