论文标题
裂纹传播模拟而无需裂纹跟踪算法:嵌入式不兼容模式的嵌入式不连续性公式
Crack propagation simulation without crack tracking algorithm: embedded discontinuity formulation with incompatible modes
论文作者
论文摘要
我们表明,为了模拟准脆性二维固体中的裂纹繁殖,可以使用具有不相容模式的嵌入式强不连续性四边形有限元元素来获得非常好的效果。更重要的是,我们证明可以在不使用裂纹跟踪算法的情况下获得这些结果。因此,将模拟具有几种裂纹的裂纹模式,包括分支,可能是可能的。避免跟踪算法的避免主要是通过在裂纹成核中应用新颖的局部(高斯)标准来实现的,这决定了嵌入定位线及其位置和方向的时间。我们用热力学框架来处理裂纹的演变,其软化变量描述了材料降解的内部耗散机制。如数值示例所示,网格中的许多元素可能会出现裂纹,但是只有其中一些元素实际上打开和/或滑动,消散断裂能,并最终形成裂纹模式。新颖的方法已经针对静态和动力学实施,计算出的困难示例的结果(包括Kalthoff的测试)说明了其非常令人满意的性能。它有效地克服了对标准嵌入的强不连续制剂的不利限制,即仅模拟单个裂纹的传播。此外,它在计算上快速且直接实现。我们的数值解决方案与实验测试的结果相匹配,并在裂纹模式,消散的断裂能和负载解散曲线方面报道了数值结果。
We show that for the simulation of crack propagation in quasi-brittle, two-dimensional solids, very good results can be obtained with an embedded strong discontinuity quadrilateral finite element that has incompatible modes. Even more importantly, we demonstrate that these results can be obtained without using a crack tracking algorithm. Therefore, the simulation of crack patterns with several cracks, including branching, becomes possible. The avoidance of a tracking algorithm is mainly enabled by the application of a novel, local (Gauss-point based) criterion for crack nucleation, which determines the time of embedding the localisation line as well as its position and orientation. We treat the crack evolution in terms of a thermodynamical framework, with softening variables describing internal dissipative mechanisms of material degradation. As presented by numerical examples, many elements in the mesh may develop a crack, but only some of them actually open and/or slide, dissipate fracture energy, and eventually form the crack pattern. The novel approach has been implemented for statics and dynamics, and the results of computed difficult examples (including Kalthoff's test) illustrate its very satisfying performance. It effectively overcomes unfavourable restrictions of the standard embedded strong discontinuity formulations, namely the simulation of the propagation of a single crack only. Moreover, it is computationally fast and straightforward to implement. Our numerical solutions match the results of experimental tests and previously reported numerical results in terms of crack pattern, dissipated fracture energy, and load-displacement curve.