Influence of loading rate on the mode II fracture characteristics of SCC samples: Experiments and numerical simulations

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2024-10-20 DOI:10.1016/j.tafmec.2024.104729

Ri-hong Cao, Hailong Yu, Xianyang Qiu, Hang Lin, Mingyu Cao

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Abstract

This paper explores the influence of loading rate on mode II fracture failure in rock. Impact experiments were performed on samples of SCC at five different impact pressures via an SHPB system. This study reveals the correlations among the peak load, fracture toughness, and dynamic elastic modulus of rock mode II fractures under diverse loading rates, as well as the alterations in fracture trajectories. Simultaneously, PFC3D discrete element software has been adopted to numerically simulate the experiments and analysis of the fracture process of rocks and the variations in crack quantity and energy from a microscopic perspective. The results suggest that dynamic mode II fracture tends to increase as the loading rate increases and that the loading rate affects the fracture failure trajectory of a sample. Concurrently, as loading increased, the percentage of shear cracks in the samples gradually decreased, whereas the proportion of tensile cracks gradually increased, indicating that the samples experienced compressive stress after mode II fracture occurred at high loading rates. The proportion of energy absorbed by the samples for crack initiation and development, as well as the kinetic energy of the particles, initially tends to decrease but then increases with increasing loading rate, which is related to whether the loading rate generates secondary cracks. It is hypothesized that there exists a critical loading rate that triggers secondary cracks in SCC samples.

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加载速率对 SCC 样品模式 II 断裂特征的影响：实验和数值模拟

本文探讨了加载速率对岩石中模式 II 断裂破坏的影响。通过 SHPB 系统对 SCC 样品进行了五种不同冲击压力下的冲击实验。该研究揭示了不同加载速率下岩石模式 II 断裂的峰值载荷、断裂韧性和动态弹性模量之间的相关性，以及断裂轨迹的变化。同时，采用 PFC3D 离散元软件进行数值模拟实验，从微观角度分析了岩石的断裂过程以及裂缝数量和能量的变化。结果表明，随着加载速率的增加，动态模式 II 断裂有增加的趋势，加载速率会影响样品的断裂破坏轨迹。同时，随着加载速率的增加，样品中剪切裂纹的比例逐渐减少，而拉伸裂纹的比例逐渐增加，这表明在高加载速率下发生模式 II 断裂后，样品受到了压应力。样品在裂纹萌发和发展过程中吸收的能量比例以及颗粒的动能最初呈下降趋势，但随着加载速率的增加又呈上升趋势，这与加载速率是否会产生二次裂纹有关。据此推测，在 SCC 样品中存在一个引发二次裂纹的临界加载速率。

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

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.