PSI - Issue 28

Adrian Loghin et al. / Procedia Structural Integrity 28 (2020) 2304–2311 A. Loghin et al. / Structural Integrity Procedia 00 (2020) 000–000

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Fig. 1: (a) 3D representation of the specimen; (b) Typical mesh used in the simulations; (c) Mesh refinement assigned to the crack surface and crack front mesh pattern.

Fig. 2: (a) Crack front increments generated in one simulation; (b) Close-up view near the hole. The yellow plane is used to extract crack path along the front face of the model.

These two simulations, designed to evaluate the influence of loading application mode, made use of the same mesh density and pattern along the crack front for each increment to minimize mesh related variability in the predicted crack paths. Comparison of the experimental crack path and the two predictions provided in Figure 3 show that the crack path in not sensitive to these two di ff erent modeling modes for applying the load. The crack path is extracted at the free surface of the model in all comparisons against the experimental data and, as it can be seen in Figure 1c, crack path profile does not change much along the crack front length. In a second sensitivity assessment, the loading mode (uniform loading at the pin-specimen hole engagement) was fixed while the mesh pattern and crack front increment assigned throughout the crack propagation simulation, were varied. Table 1 provides the mesh assignment di ff erences of the four simulations while Figure 4 shows the associated predicted crack paths. A detailed mesh sensitivity study can be achieved by considering di ff erent mesh patterns and performing complete crack propagation simulations similar to the assessment provided by Loghin and Ismonov (2020). Based on these two nominal geometry sensitivity assessments, it was concluded that 1. uniform loading applied at the pinholes is an appropriate loading mode, 2. the mesh refinement associated with Model#2 is su ffi cient to perform all simulations for assessing crack path variability due to o ff -nominal geometric deviations.