On Fatigue Crack Growth and a Study of Some of the Stress History Parameters Affecting Fatigue Life.

摘要

The purpose of the study was to gain further insight of how structural fatigue life is influenced by various statistical properties of the applied load history. The main aim in the present study was to maintain careful control over the input parameters, such as the ratio of the maximum fluctuating stress to the rms value, or the zero crossing values associated with the load history and its time derivative. Control was also made over the initiation of crack growth. Loading of Aluminum alloy 2024 was composed of a constant mean load and a super-imposed fluctuating component. The fluctuating component was achieved through a combination use of several sine-wave generators. Prior to giving the results of the tests, some consideration is given to crack growth behavior and its analytic form. From this consideration, the basis for a generalized crack growth analysis is outlined.