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多轴非比例疲劳荷载状态下的构件寿命预测问题非常复杂,其中一个重要的工作是对于本构关系的预测。在材料弹性状态下这个问题相对简单,但当材料进入塑性以后,材料的屈服面及非比例效应都会随着塑性应变的增加发生相应改变,因此这个过程中等向强化、随动强化及非比例强化效应都必须被考虑。介绍了一种广义的多轴非比例疲劳荷载状态下计算材料本构关系的方法,该方法引入非线性多屈服面模型,通过塑性应变增量反映强化效应对材料广义硬化模量的影响,最终预测材料的应力应变关系。316L不锈钢多轴非比例疲劳实验验证了其方法的有效性。
The problem of component life prediction under multi-axial non-proportional fatigue loading is very complicated. One of the most important tasks is to predict the constitutive relationship. This problem is relatively simple in the material elastic state, but when the material enters the plasticity, both the yield surface and the non-proportional effect of the material will change correspondingly with the increase of the plastic strain, so the process of isotropic strengthening, following strengthening and non-proportional strengthening The effects must all be considered. A generalized method for calculating the material constitutive relationship under multi-axial non-proportional fatigue loading is introduced. The method introduces a nonlinear multi-yield surface model, which reflects the effect of strengthening effect on the material’s generalized hardening modulus through plastic strain increment. Finally, Predict the material’s stress-strain relationship. 316L stainless steel multi-axial non-proportional fatigue test to verify the effectiveness of the method.