PSI - Issue 66

32 Carl H. Wolf et al. / Procedia Structural Integrity 66 (2024) 26–37 Carl H. Wolf, Sebastian Henkel, Christian Düreth, Maik Gude and Horst Biermann / Structural Integrity Procedia 00 (2025) 000–000 7 a . This can lead to deviations in the outcome, as the results are only as good as the assumptions. Furthermore, so far only calculations under uniaxial loading have been carried out, as shown in Figure 3a. 3. Results 3.1. Numerical investigation fur uniaxially loaded specimen The determination of the energy release rate for a uniaxially loaded specimen is based on the crack path shown in Figure 3 a. For this purpose, a fit function was determined along the measurement points, cf. Figure 5 . This function was then used to calculate the cyclic energy release rates for a straight crack path according to reference [11].

Figure 5: Fit for the energy release rate for a crack path according to the load case given in Figure 3a using the J -integral.

3.2. Fatigue life The S-N plot in Figure 6 shows that the fatigue life increases with increasing fabric thickness. It is clear that the fatigue life is always lowest for low fabric thicknesses, compare red measuring points for specimens with a fabric with a basis weight of 160 g/m² with orange measuring points for specimens with a fabric with a basis weight of 200 g/m² and green measuring points for specimens with a fabric with a basis weight of 245 g/m² in Figure 6 . Furthermore, it can be seen that the lifetime decreases as expected with increasing force amplitude. The plot also shows that the lifetime increases with increasing static compressive loading, cf. circles, squares and crosses in Figure 6 . However, it can also be seen that the scatter of the lifetimes increases with increasing compressive force amplitude, cf. circles for uniaxial loading at lower load cycles with squares and crosses at the same force amplitude at higher load cycles in Figure 6 .

Figure 6: S-N plot for the investigated specimens.