Introduction

Weight-optimized component design and the resulting estimation of the service life or service life of metallic materials require a comprehensive understanding of fatigue processes and the systematic investigation of fatigue behavior. For reasons of time and cost alone, many components can usually neither be built as prototypes nor tested as such under operating conditions.

The relationship between stress amplitude and service life is usually plotted in the form of Wöhler curves, and a power approach according to Basquin [1] is often used for the mathematical description in stress-controlled testing. Wöhler curves and the damage accumulation hypotheses based on them according to Palmgren and Miner [2], as well as various modifications, currently still frequently form the basis for estimating service life and generate correspondingly controversial discussions, because it has been proven in many experiments that the underlying assumption of linear damage accumulation as a result of the stresses that occur is not valid.

To determine Wöhler curves, a large number of fatigue tests are usually required. With a view to reducing the number of tests and thus also the costs, while at the same time improving the agreement between calculation and experiment, various short-term methods have been developed in recent years that take account of nonlinear damage accumulation (e.g. [3-5]). In this context, the potentials of non-destructive testing (NDT), digitization of metrology, and signal processing are combined to achieve a significant gain of information regarding the fatigue behavior. This combination pursues the consistent goal of extracting more material information from fewer fatigue tests, while at the same time increasing the complexity of the testing tasks involved.