arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2207.09362cond-mat.mtrl-sciphysics.app-ph
收藏

用相场法模拟含空洞材料中的裂纹轨迹

Crack trajectories in materials containing voids via phase-field modelling

Riccardo Cavuoto, Pietro Lenarda, Diego Misseroni, Marco Paggi, Davide Bigoni

摘要:

材料中的裂纹扩展受到非均匀性的强烈影响,非均匀性使裂纹轨迹偏离直线并严重影响失效。增加裂纹弯曲度与断裂韧性的增强有关,而通常裂纹甚至可以在撞击空隙时停止,这释放了应力集中。因此,裂纹轨迹的确定在材料和机械零件的失效设计中是重要的。最近开发的相场法(AT1和AT2模型),基于变分方法的损伤定位,被认为是特别适合于描述复杂的裂纹轨迹。这一信念是通过比较PMMA板,这已被设计在一个新的方式,突出的缺口和圆孔断裂传播的影响,模拟和光弹性实验检查。后者示出从缺口开始,并强烈吸引空隙。当一个空洞被击中,断裂被阻止,除非空洞包含一个缺口在其内部表面,从一个新的裂纹成核和传播。不同的力学模型进行了测试,其中裂缝开始和增长(i.)在模式I紧凑张力下,(ii.)四点弯曲和(iii.)在压缩含有圆孔的样品时间接产生的拉伸应力。实验表明,断裂扩展可以设计成在不同的曲折路径中发展,包括多次停止和二次成核。与一个特设的实施版本的AT 1和AT 2相场方法(配备频谱分解,其中裂纹被模拟为一个高度局部化的区域的损伤积累)进行的模拟显示与实验密切一致,因此确认该方法的有效性和其潜力的机械设计。

英文摘要:

Fracture growth in a material is strongly influenced by the presence of inhomogeneities, which deviate crack trajectories from rectilinearity and deeply affect failure. Increasing crack tortuosity is connected to enhancement of fracture toughness, while often a crack may even be stopped when it impinges a void, which releases the stress concentration. Therefore, the determination of crack trajectories is important in the design against failure of materials and mechanical pieces. The recently developed phase-field approach (AT1 and AT2 models), based on a variational approach to damage localization, is believed to be particularly suited to describe complex crack trajectories. This belief is examined through a comparison between simulations and photoelastic experiments on PMMA plates, which have been designed in a new way, to highlight the effects of notches and circular holes on fracture propagation. The latter is shown to initiate from a notch and to be strongly attracted by voids. When a void is hit, fracture is arrested, unless the void contains a notch on its internal surface, from which a new crack nucleates and propagates. Different mechanical models are tested where fracture initiates and grows (i.) under Mode I compact tension, (ii.) four-point bending and (iii.) a tensile stress indirectly generated during compression of samples containing a circular hole. The experiments show that the fracture propagation may be designed to develop in different tortuous paths, involving multiple arrests and secondary nucleation. Simulations performed with an ad hoc implemented version of the AT1 and AT2 phase-field methods (equipped with spectral decomposition, in which a crack is simulated as a highly localized zone of damage accumulation) are shown to be in close agreement with experiments and therefore confirm the validity of the approach and its potentialities for mechanical design.

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。

↑