Level Crossing Cycle Counting

Variable amplitude loadings are generally divided in two types  

For a constant amplitude spectrum the corresponding pdf reduces to a single peak without tails with the standard deviation to mean value ratio equal zero, s/x = 0. If the load history is non-symmetric also the relative peaks distribution 

000 — 30,000 = 10,000 which is 25 % of all cycles. On the contrary, if lower amplitude loads prevail over the larger ones that are relatively few, then a steep load spectmm is obtained, as shown in Fig. 8.9. In this case, high loads with a peak value exceeding 90 % of the maximum occur only 5 times whereas there are 

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