Coupling Between Mesoplasticity and Damage in High-cycle Fatigue
Coupling Between Mesoplasticity and Damage in High-cycle Fatigue
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DOI：
10.1177/1056789506067935
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发表时间：
2007-10
影响因子：
4.2
通讯作者：
L. Flacelière;F. Morel;A. Dragon
中科院分区：
文献类型：
--
作者：
L. Flacelière;F. Morel;A. Dragon
在高周制度的多轴疲劳载荷导致局部介观塑性应变，发生在一些个别晶粒的优先方向，为大多数金属材料。在这种疲劳状态下，裂纹萌生建模是困难的，因为机制操作的尺度不是工程尺度（宏观尺度），局部塑性和损伤同时起作用。本文介绍了一种基于细观塑性和局部损伤之间的相互作用的损伤模型的无限和有限的疲劳寿命区。通过一个简单的本地化规则，它连接的宏观尺度与介观的一个，并在这里提出的模型，它描述了细观塑性和损伤增长的耦合效应占几个显着的影响。内部状态变量的不可逆热力学概念被用来保持广泛的描述塑性流动和损伤事件之间的平衡。循环硬化行为是由各向同性和运动硬化相结合的规则描述，而损伤演化显着的累积塑性细观应变。在这项研究中，预测进行了比较，在低碳钢（C36）在不同的加载模式下进行的疲劳试验。所有的实验都是在同相加载条件下进行的：反向拉伸，扭转，和拉扭组合。还通过拉伸试验研究了平均应力效应。任何加载模式下的预测Wöhler曲线都可以很容易地用这个模型获得，但这种方法的主要特点是确保细观参数之间的明确联系，如单个晶粒的硬化行为和随后的局部损伤。
The multiaxial fatigue loading in the high-cycle regime leads to localized mesoscopic plastic strain that occurs in some preferential directions of individual grains for most metallic materials. Crack initiation modeling is difficult in this fatigue regime because the scale where the mechanisms operate is not the engineering scale (macroscopic scale), and local plasticity and damage act simultaneously. This article describes a damage model based on the interaction between mesoplasticity and local damage for the infinite and the finite fatigue life regimes. Several salient effects are accounted for via a simple localization rule, which connects the macroscopic scale with the mesoscopic one, and by the model presented here, which describes the coupled effects of mesoplasticity and damage growth. Irreversible thermodynamics concepts with internal state variables are used to maintain a balance between extensive descriptions of plastic flow and damage events. Cyclic hardening behavior is described by a combined isotropic and kinematic hardening rule while the damage evolution is governed notably by the accumulated plastic mesoscopic strain. In this study, predictions are compared to fatigue tests performed on a mild steel (C36) under different loading modes. All the experiments are carried out under in-phase loading conditions: reversed tension, torsion, and combined tension—torsion. The mean stress effect is also studied through tests conducted under tension. The predicted Wöhler curves under any loading mode can be readily obtained with this model, but the main feature of this approach is to ensure a clear link between the mesoscopic parameters like the hardening behavior of individual grains and the subsequent local damage.