PSI - Issue 38

Ronald Schrank et al. / Procedia Structural Integrity 38 (2022) 30–39 Author name / Structural Integrity Procedia 00 (2021) 000 – 000

32

3

The simplified test has to be designed to reproduce fatigue damage at significant locations of the part (“hotspots”) from the full test in the best way. Discrepancy (error) in fatigue damage has to be minimized, a typical objective of optimization. Typical applications for solving this optimization task mainly follow these two philosophies: • Classic strategies (for “manual” processing) • New strategies supported by numerical methods (for automated processing) Both philosophies will be outlined next.

Fig. 2. Optimization problem

2. General method of fatigue damage calculation Analyses of fatigue damage are necessary for both, full test and simplified test. They are performed using a numerical approach based on local stress calculation by the Finite-Element-Method (FEM) and subsequent fatigue calculation.

Fig. 3. Typical process of fatigue analysis.

Since fatigue- critical locations (“hotspots”) of the structural part are not known beforehand, calculation of fatigue damage is carried out as a “full - field” procedure, resulting in a fatigue damage distribution over the entire surface of the structural part. This procedure requires the application of fatigue software which provides interfaces to finite element solvers that provide local stresses again.