PSI - Issue 75

Aijia Li et al. / Procedia Structural Integrity 75 (2025) 318–333 Aijia Li, Christian Garnier, Marie-Laetitia Pastor, Xiaojing Gong, Clément Keller/ Structural Integrity Procedia (2025) 11

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Fig. 9. distribution of the stresses in the fiber direction (S11 stress) and perpendicular to the fiber direction (S22 stress) on the 1 st layer and 9 th layer of the designed specimen

4.3. Result of the validation After applying a tension-tension biaxial fatigue loading to the designed specimen, it is possible to locate the initial failure and predict the stress field evolution. When looking at the cross-ply specimen under the maximum load, Fig. 10 (a) illustrates that this design can impose a first failure at the edge of the gauge region for the cross-ply layup, as the maximum Tsai-Hill failure factor of 3.6 is located in the gauge region. And the stress distribution, like the stress in the fiber direction (S11 stress components), has a small deviation that allows an ideal observation condition of the stress and strain field. Similarly, the quasi-isotropic specimen also has a first failure (maximum Tsai-Hill failure factor of 1.89) and a uniform stress field in the gauge region, as shown in Fig. 10 (b). It is worth noticing that the stress concentration problem on the transition cannot be avoided, but the possibility of failure caused by the problem can be greatly reduced by improving a larger transition. In brief, the positive result obtained from the mechanical simulation proves that the specimen design meets the first and second criteria.