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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The following options are available for the calculation type: • A time function is calculated from static load patterns and assigned time functions (fatigue collective). • A time function is calculated from a modal basis of the stresses and time -varying participation factors of the modes. This includes the transformation from the frequency to the time domain (fatigue timehistory). • The time function is given directly from the FE M calculation. This is usually the case with nonlinear analyses (fatigue timeline). 5. Mesh variation example It has been proven that finer meshes give more accurate solutions. Fine meshes are necessary to accurately describe the geometry of components, to represent their stiffness behavior accurately and for semi-automatic meshing. An example of a yoke is used here with different meshes to show the high efficiency of the new integrated approach.

Fig. 12. Yoke example in three different mesh refinements.

The yoke is meshed in three different refinement states from 8,810 to 34,826 to 146,810 fatigue nodes. More details about the mesh size are shown in figure 12. For the fatigue timeline analysis two load pattern are used with 164,548 time steps each, 40 cutting planes and 200 rainflow stress classes per node. The run times (Fig. 13) are for the complete run times with stress and fatigue analysis.

Fig. 13. Run time comparison for different mesh sizes for stress and fatigue analysis.

The run times confirm the high efficiency of the new integrated approach. The high-performance infrastructure of the FE solver leads to very short run times for the complete process. The decisive factors are that manual intermediate steps are no longer required, direct access to one single database is established and that a very efficient parallelization approach is realized for all program parts.