On evolution laws of anisotropic damage
On evolution laws of anisotropic damage
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DOI：
10.1016/0013-7944(89)90130-6
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发表时间：
1989
影响因子：
5.4
通讯作者：
C. Chow;T. Lu
中科院分区：
文献类型：
--
作者：
C. Chow;T. Lu
本文重点研究了各向异性损伤演化规律的发展。以微裂纹和微腔的形式导致宏观力学性能变化的材料损伤在现象学上进行了建模，其中一些细节失真和模糊，认为材料性能变化的程度可以作为适当的间接测量损伤。文中还描述了实验观察到的损伤硬化现象。然后利用不可逆过程的既定热力学理论推导出材料逐渐退化的本构方程，并提出了一个新的能量等效假设，而不是迄今为止提出的应变或变形等效的限制性假设。假设塑性流动和损伤过程中的能量可以不耦合，以解析形式推导出损伤变量“损伤能量释放率”的热力学共轭力。根据亲和空间的损伤面概念和最大损伤耗散原则，建立了各向异性损伤的演化规律。研究的一个重要成果是确定了一个新的损伤特征张量J，该张量既能准确地描述损伤生长的各向异性性质，又简单，只需从标准拉伸试验中确定一个未知参数。
This paper is focused on the development of evolution laws of anisotropic damage. Material damage in the form of microcracks and microcavities leading to macro-mechanical property variations is modelled phenomenologically with some distortion and blurring of fine details, arguing that the extent of material property changes may serve as an appropriate, indirect measure of damage. The experimentally observed phenomenon of damage hardening is also described. The well-established thermodynamic theories of irreversible processes are then appealed for deriving constitutive equations of the materials suffering from progressive deterioration, together with a new hypothesis of energy equivalence instead of the restrictive hypothesis of strain or deformation equivalence hitherto proposed. Thermodynamic conjugate force of the damage variable, the “damage energy release rate”, is deduced in analytical form by assuming that the energy involved in the plastic flow and damaging processes can be uncoupled. Evolution laws of anisotropic damage are established following the concept of a damage surface in the space of affinities as well as the principle of maximum damage dissipation. An important outcome of the investigation is the identification of a new damage characteristic tensor J which can accurately describe the anisotropic nature of damage growth and yet is simple with only one unknown parameter to be determined from a standard tension test.