Comments on linear summation hypothesis of fatigue failures

This paper presents a comparative analysis of results of fatigue life calculations with the use of the linear summation hypothesis of fatigue failures (LHSUZ), confronted with experimental test results. The calculations and fatigue tests were performed for variable amplitude(VA), two-step and ten-step loading conditions , both in the low-cycle fatigue (LCF) and high-cycle fatigue ( HCF) range, for the case of C45 steel as an example. Experimental verification of the hypothesis LHSUZ did not revealed any significant influence of load level and form of load spectrum on conformity of results of the calculation by using the LHSUZ, to results of fatigue tests on C45 steel. However, it enabled to assess magnitude of a correction factor which appears in the considered linear hypothesis.