A CDM-like constitutive law for predicting degradation of strength and ductility of steel subjected to cyclic loading
A CDM-like constitutive law for predicting degradation of strength and ductility of steel subjected to cyclic loading
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DOI：
10.1016/j.ijplas.2022.103237
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发表时间：
2022-02
影响因子：
9.8
通讯作者：
Y. Shintaku;S. Tsutsumi;K. Terada
中科院分区：
文献类型：
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作者：
Y. Shintaku;S. Tsutsumi;K. Terada
本文提出了嵌入内聚裂纹和塑性损伤的类连续损伤模型本构律，以表征循环荷载作用下钢的强度和延性退化。所提出的本构律适用于任意的基于超弹性的塑性模型，利用变形梯度乘法分解为分离诱导的、弹性的和塑性的部分，并加入附加的具有记忆面的各向同性硬化规则。将各向同性和运动硬化的弹塑性变形用henky模型表示，而将材料分离引起的分离变形梯度嵌入到基于超弹性的塑性模型中。此外，在所选的CTSL中加入塑性损伤变量来降低临界能量释放率。此外，引入了一个新的材料常数来调节CTSL内聚牵引力临界值与材料分离宽度的比值。另一方面，在传统的各向同性和运动硬化规则的基础上，增加了依赖于记忆表面的附加硬化规则，以反映不同循环加载范围内塑性变形的差异。通过实验确定了材料参数，验证了模型的有效性。实验结果表明，本文提出的本构律能够预测钢在循环加载后的抗拉强度和断裂伸长率的退化。
This paper presents a continuum-damage-model-like constitutive law embedding cohesive cracks with plasticity-induced damage to represent the degradation of strength and ductility of steel under cyclic loading. The proposed constitutive law accommodates an arbitrary hyperelasticity-based plastic model with the use of the deformation gradient multiplicatively decomposed into separation-induced, elastic and plastic parts, and incorporated with an additional isotropic hardening rule endowed with a memory surface. While the elastic–plastic deformation along with isotropic and kinematic hardening is represented by a Hencky-type model, the separation-induced deformation gradient due to material separation is employed to embed an arbitrary cohesive traction separation law (CTSL) into the hyperelasticity-based plastic model. Also, a plasticity-induced damage variable is added to the selected CTSL to degrade the critical energy release rate. In addition, a new material constant is introduced to adjust the ratio between the critical values of cohesive traction and material separation width in the CTSL. On the other hand, the additional hardening rule depending on memory surface is appended in conjunction with the conventional isotropic and kinematic hardening rules to reflect the difference in plastic deformation with various ranges of cyclic loading. Several experiments are conducted to identify the material parameters and verify the validity of the proposed model. By reference to the experimental results, the capability of our proposed constitutive law is demonstrated in predicting the degradation of tensile strength and breaking elongation of a steel after cyclic loading.