The role of secondary voids in the mechanism of ductile fracture at a crack tip

IF 3.4 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials Pub Date : 2024-10-01 DOI:10.1016/j.mechmat.2024.105170

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引用次数: 0

Abstract

The mechanics and mechanisms of ductile fracture, ahead of a blunting crack tip, have been studied extensively. Several computational studies analyzing the effect of initial void volume fraction, void shape, void spatial distribution and the mode of loading (

K_{I}, K_{I I}

etc.) on crack-void interaction and its consequence on the mechanism of fracture have been reported. The influence of small size secondary voids on the failure of ligament between the large primary voids and, hence, on fracture toughness has been analyzed using the Gurson-type homogenized models of ductile fracture. In the present work, the two populations of voids ahead of a crack tip are modeled discretely. A plane strain, central line cracked boundary layer model under small-scale yielding is considered. The role of initial shape and spatial distribution of secondary voids, matrix strain hardening and mode of imposed loading in the mechanism of ductile crack growth initiation and advance is analyzed in detail. For completeness sake, numerical calculations are also performed using a homogenized representation of the secondary voids. The results so obtained are then compared with the predictions based on discrete modeling of the secondary voids. Our numerical studies revealed that plastic flow localization resulting from a small initial volume fraction of favorably distributed secondary voids may alter the path of crack growth initiation and advance, thus, influencing the ductile fracture toughness.

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二次空隙在裂纹尖端韧性断裂机制中的作用

人们对钝化裂纹尖端前的韧性断裂的力学和机理进行了广泛的研究。一些计算研究分析了初始空隙体积分数、空隙形状、空隙空间分布和加载模式（KI、KII 等）对裂纹-空隙相互作用的影响及其对断裂机制的影响。利用古尔松类型的韧性断裂均质化模型，分析了小尺寸次生空隙对大尺寸原生空隙之间韧带断裂的影响，以及对断裂韧性的影响。在本研究中，裂纹尖端前的两个空隙群被离散地建模。考虑了小尺度屈服下的平面应变、中心线裂纹边界层模型。详细分析了次生空隙的初始形状和空间分布、基体应变硬化和外加载荷模式在韧性裂纹生长和扩展机制中的作用。为完整起见，还使用二次空隙的均质化表示进行了数值计算。然后将计算结果与基于二次空隙离散建模的预测结果进行比较。我们的数值研究表明，由于有利分布的次生空隙的初始体积分数较小而导致的塑性流动局部化可能会改变裂纹生长的起始和推进路径，从而影响韧性断裂韧性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Mechanics of Materials 工程技术-材料科学：综合

CiteScore

7.60

自引率

5.10%

发文量

243

审稿时长

46 days

期刊介绍： Mechanics of Materials is a forum for original scientific research on the flow, fracture, and general constitutive behavior of geophysical, geotechnical and technological materials, with balanced coverage of advanced technological and natural materials, with balanced coverage of theoretical, experimental, and field investigations. Of special concern are macroscopic predictions based on microscopic models, identification of microscopic structures from limited overall macroscopic data, experimental and field results that lead to fundamental understanding of the behavior of materials, and coordinated experimental and analytical investigations that culminate in theories with predictive quality.