【摘要】 由复相钢CP800制造的汽车底盘结构件如扭力梁，其成形过程中产生的预弯曲变形对其疲劳寿命具有重要影响。然而预弯曲变形对CP800钢疲劳性能影响的相关研究尚未见报道，因此本工作通过冲压对复相钢CP800施加了预弯曲应变，并揭示了预弯曲应变对CP800复相钢疲劳性能的影响。研究发现，预弯曲明显缩短了CP800钢的疲劳寿命，且该效果随平均应力的减小更加显著。在相同应力条件下，CP800钢预弯曲后的总应变幅值范围低于原板料，表明CP800钢经过预弯曲后，其抵抗宏观循环变形的能力有所提高，这与在单调变形中残余应力所导致的变形抗力降低不同。最后，基于Basquin理论建立了无预弯曲及预弯曲试样的S-N曲线，并结合ABAQUS/Fe-safe软件验证了基于S-N曲线的疲劳寿命预测模型的准确性。本工作为复相钢在工业应用中的构件服役寿命设计和预测提供了研究基础。更多还原

【Abstract】 Automobile structural parts made by complex phase steel CP800, such as torsion beam, will suffer pre-bending deformation during the process of manufacture, which affects fatigue properties. However, related studies for the effect of pre-bending on fatigue property of CP800 have not been reported. Therefore, in this work, pre-bending strain was applied to the CP800 by stamping, and the effect of pre-bending on the fatigue behavior of CP800 was studied. Pre-bending has a negative effect on the fatigue life of CP800, and the effect is more obvious with decreasing mean stress. Under the same stress condition, the range of total strain amplitude of pre-bending specimens is lower than that of as-received sample. It means that after pre-bending deformation, its resistance to macroscopic cyclic deformation was improved, which is different to the phenomenon that the resistance decreased due to the residual stress during monotonous deformation. Finally, S-N formulas of as-received and pre-bending specimens were established based on Basquin equation, and the accuracy of the fatigue life prediction model based on S-N curve is verified by software ABAQUS/Fe-safe. In general, this work provides a research basis for the design and prediction of service life of structural parts in industrial applications.更多还原