In this paper, the effects of pre-ratcheting deformations upon the fatigue life of aluminum 2024 welded specimen is studied. Ratcheting, as a characteristic of unbalanced cyclic plasticity, can accelerate fatigue damage or even acts as a failure mode by itself. In this study the combination of two levels of ratcheting loadings and their interactions are studied. In this regard, some tests are performed. The effects of such factors as mean stress, stress amplitude, stress frequency and the number of ratcheting cycles are investigated. The stress-controlled fatigue tests are carried out at ambient temperature. The results reveal how the mixed- ratcheting states can reduce the fatigue life expectancy of plain and welded specimens.

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