PSI - Issue 19

J. Rudolph et al. / Procedia Structural Integrity 19 (2019) 575–584 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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IV. Determination of the history of the equivalent stress range (equal to twice the variation of the shear stress acting in the analysis plane), between any point in time and the origin point in time chosen as shown in Figure 8. V. Identification, counting and determination of the range of the elementary fatigue cycles, on the basis of the variations of the equivalent stress range determined using the chosen origin point in time as starting point, and then calculation of the corresponding cumulative damage as shown in Figure 9. VI. Repetition of steps III to V of the procedure, for different origin points in time so as to determine that which leads to the greatest cumulative damage. VII. Repetition of steps I to VI of the procedure for different analysis planes so as to determine that which leads to the greatest cumulative damage (that plane is the critical plane). The greatest resulting cumu lative usage factor (CUF max ) is relevant for fatigue assessment (It has to be shown that CUF max < 1.0).

Fig. 6. Selection of an analysis plane

Fig. 7. Determination of stress history

Fig. 8. Determination of the history of the equivalent stress