PSI - Issue 57

Laurent Dastugue et al. / Procedia Structural Integrity 57 (2024) 355–364 Michael Klein et. al./ Structural Integrity Procedia 00 (2019) 000 – 000

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3.2. Accuracy -Gradients Accuracy – Gradients: For more accurate damage calculations stress gradients normal to the surface are used. These nodal point results are only calculable if the stresses inside the structure are known. For the classic process these leads to additional required data, which also must be transferred by file. Again, these results are simply internal available from the database for the new integrated process.

Fig. 8. Stress results (left) and nodal stress gradients normal to the surface (right).

In addition, the gradient accuracy is much higher, because the normal direction is in best quality and the element shape functions are internally exclusive available (Fig. 9). The gradients are much better than the often-used simple finite differences. Figure 8 shows the stress results and the high accuracy nodal stress gradients normal to the surface which were calculated with considering the element shape functions and the interior stress data.

Fig. 9. Computation of nodal point stress gradients.

3.3. Additional data efficiency – “On -the- fly” Additional data efficiency – “On -the- fly” : Integration makes on-the-fly calculation of results possible. Instead of saving all intermediate results like stress data, including gradients, stack wise until they are used later to calculate damage results, the integrated approach allows to calculate the final result stepwise and to release the intermediate results right away from storage. This allows former impossible model sizes. For the stress results (Fig. 10) no storage