Effect of pre-strain on high cycle fatigue property of TWIP steel

A commonly used material in vehicle structure is twinning-induced plasticity (TWIP) steel. In addition, during auto safety structural parts process, the material is pre-strained to different levels. Therefore, the influence of pre-straining on fatigue life needs to be examined for design and life assessment. Based on the current test data, due to the different types of steel and loading methods, the fatigue life of the material will show an increase or decrease with the increase of pre-strain level. The results of this study are compared with the recommended S-N fatigue, and the applicability and conservative levels of fatigue life curves are discussed to consider the influence of material pre-strain on the fatigue life assessment of automotive structural components.