摘要
采用三点弯曲测试法对3组预置初始裂纹的矩形煤样开展Ⅰ型断裂试验,探讨了Ⅰ型断裂的裂纹扩展路径、应力分布以及裂纹张开-位移曲线,并与实验结果进行对比。结果表明,煤样断裂裂纹均从预制裂纹顶端起裂,扩展路径近似为直线,呈典型的张拉破坏形式。其中内部裂纹出现前,水平应力主要集中在直裂纹两侧;内部裂纹出现后,直裂纹顶端出现应力集中并逐步向上发展,煤样断裂瞬间应变率呈显著的非线性增长特征。由于相场模型同时涵括了基于强度的起裂准则、基于能量的扩展准则以及基于变分原理的裂缝路径判据,相场模型不仅适用于带初始缺陷煤样的开裂行为模拟,而且适用于无初始缺陷煤样的损伤破坏全过程分析,这可为煤样的力学失效预测和防护提供有益的参考。
In this paper,the three-point bending test method is used to carry out the type I fracture test on three sets of rectangular coal samples with pre-exiting initial cracks,and the crack propagation path,stress distribution and crack opening-displacement curve of the type I fracture are discussed,and compared with the experimental results.The results show that the fracture cracks of the coal samples all start from the top of the prefabricated cracks,and the propagation path is approximately a straight line,showing a typical tension failure form.Before the appearance of internal cracks,the horizontal stress is mainly concentrated on both sides of the straight cracks;after the appearance of internal cracks,the stress concentration appears at the top of the straight cracks and gradually develops upwards,and the instantaneous strain rate of the fracture of the coal sample shows a significant nonlinear growth characteristic.Since the crack initiation criterion based on strength,the propagation criterion based on energy and the fracture path criterion based on variational principle are included at the same time,the phase field model is not only suitable for the cracking behavior simulation of coal samples with initial defects,but also suitable for The analysis of the whole process of damage and destruction of coal samples can provide a useful reference for the prediction and protection of mechanical failure of coal samples.
作者
武雷刚
申强
路杰
WU Lei-gang;SHEN Qiang;LU Jie(School of Applied Science,Taiyuan University of Science and Technology,Taiyuan 030024,China;Jinneng holding group Shanxi Sanyuanfuda Coal Industry Co.,Ltd.,Changzhi Shanxi 046013,China)
出处
《太原科技大学学报》
2025年第6期587-591,共5页
Journal of Taiyuan University of Science and Technology
基金
国家自然科学基金(12002230)
山西省研究生创新项目(2022Y688)
太原科技大学博士启动基金(20192005)。
关键词
相场法
三点弯曲
脆性断裂
煤炭
有限元
phase-field method
three-point bending
brittle fracture
coal
finite element
