FATIGUE CRACK GROWTH AND CLOSURE THROUGH A TENSILE RESIDUAL STRESS FIELD UNDER COMPRESSIVE APPLIED LOADING

Abstract— —Fatigue crack growth and closure through a tensile residual stress field under an applied compressive loading is investigated by carrying out various applied stress ratio tests ranging from R = 0 to R = It is found that even under applied compressive loading, fatigue crack growth rates are well correlated with the effective stress intensity factor range and the behaviour of crack closure through a tensile residual stress field is uniquely controlled by an effective stress ratio which takes account of residual stresses. Consequently, the method of predicting fatigue growth rates, using da/d N vs Δ K data from residual stress-free specimens, can be successfully applied to crack growth through a tensile residual stress field. However, previously used simple assumptions may lead to non-conservative estimates of crack growth rates.