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arXiv 1705.04046cond-mat.mtrl-scimath.AP
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基于新退化函数族的高精度脆性断裂相场模型

High-accuracy phase-field models for brittle fracture based on a new family of degradation functions

Juan Michael Sargado, Eirik Keilegavlen, Inga Berre, Jan Martin Nordbotten

摘要:

基于能量最小化原理的相场断裂方法近年来得到了迅速的普及,并且特别适合于模拟复杂断裂网络中的裂纹萌生和扩展。在相场框架中,与裂纹形成相关联的表面能通过评估标量序参量及其梯度定义的泛函来计算,所述标量序参量及其梯度又描述了在扩散意义上遵循规定的正则化长度尺度的断裂。施加平稳的总能量导致耦合系统的偏微分方程,一个强制应力平衡和另一个管理相场的演变。这两个方程通过能量退化函数耦合,该函数模拟了在大块材料发生损伤时的刚度损失。在目前的工作中,我们引入了一个新的参数家庭的退化函数,旨在提高相场模型预测与裂纹成核以及现有的裂缝的传播的临界载荷的准确性。另一个目标是在断裂之前保持散装材料中的线性弹性响应。通过几个数值例子的分析,我们证明了所提出的家庭的功能,在文献中最常用的经典二次退化函数的优越性。

英文摘要:

Phase-field approaches to fracture based on energy minimization principles have been rapidly gaining popularity in recent years, and are particularly well-suited for simulating crack initiation and growth in complex fracture networks. In the phase-field framework, the surface energy associated with crack formation is calculated by evaluating a functional defined in terms of a scalar order parameter and its gradients, which in turn describe the fractures in a diffuse sense following a prescribed regularization length scale. Imposing stationarity of the total energy leads to a coupled system of partial differential equations, one enforcing stress equilibrium and another governing phase-field evolution. The two equations are coupled through an energy degradation function that models the loss of stiffness in the bulk material as it undergoes damage. In the present work, we introduce a new parametric family of degradation functions aimed at increasing the accuracy of phase-field models in predicting critical loads associated with crack nucleation as well as the propagation of existing fractures. An additional goal is the preservation of linear elastic response in the bulk material prior to fracture. Through the analysis of several numerical examples, we demonstrate the superiority of the proposed family of functions to the classical quadratic degradation function that is used most often in the literature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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