An Investigation into the Influence on the Fatigue Strength of Aluminium Alloy Parts of Load Spectrum Base Level and Residual

Author:  Jaensson, B. and Magnusson, L.
Source:  Conf Proc: ICSP-3, (p.423-430)
Doc ID:  1987001
Year of Publication:  1987
In this investigation of high-strength aluminium plate material, the influence of total surface stress in the short transverse direction on the fatigue life has been studied. The total stress was composed of surface residual stress and stress due to spectrum loading of the U-shaped specimens used. A number of residual stress levels and distributions were obtained by different combinations of shot peening, with and without preload, and static overloading. In addition, three levels of testing base stress were used. The fatigue test results indicate that the total surface stress generally is the decisive parameter in the case of short transverse loading and thus should be used in cumulative damage calculation. When shot peening was applied as the last specimen preparation step, however, fatigue crack initiation tended to take place well below the critical surface. In this case, shorter-than-calculated fatigue lives were obtained.

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