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中南大学学报(自然科学版)

Journal of Central South University

第49卷    第11期    总第291期    2018年11月

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文章编号:1672-7207(2018)11-2821-10
中低速冲击载荷作用下SCT岩石试样Ⅰ型裂纹的动态扩展行为
董玉清1, 2,朱哲明1, 2,王蒙1, 2,周磊1, 2,应鹏1, 2

(1. 四川大学 深地科学与工程教育部重点实验室,四川 成都,610065;
2. 四川大学 四川大学建筑与环境学院,四川 成都,610065
)

摘 要: 为研究侧开单裂纹三角形(SCT)岩石试样的动态扩展行为和断裂韧度,采用落锤冲击实验系统进行动态加载,通过裂纹扩展计(CPG)得到裂纹的断裂时间和扩展速度;用有限差分软件AUTODYN进行数值模拟,验证实验结果的可靠性;将实验测量的载荷条件代入有限元软件ABAQUS建立的数值模型中,得到动态应力强度因子时程曲线,通过普适函数修正后,利用断裂时间得到动态断裂韧度。研究结果表明:SCT试件构型能够较好地应用于岩石动态扩展行为的研究;砂岩的扩展韧度与裂纹扩展速度呈负相关;数值模拟得到的裂纹扩展路径与实验结果基本一致,裂纹扩展速度不为常数;岩石裂纹动态扩展过程中可能存在止裂现象,止裂韧度大于扩展韧度,但与起裂韧度相差不大。

 

关键词: 侧开单裂纹三角形试件;动态起裂韧度;动态扩展韧度;落锤冲击;数值模拟

Mode I crack dynamic propagation behavior of SCT specimens under medium-low speed impact load
DONG Yuqing1, 2, ZHU Zheming1, 2, WANG Meng1, 2, ZHOU Lei1, 2, YING Peng1, 2

1. Key Laboratory of Deep Underground Science and Engineering of Ministry of Education,
Sichuan University, Chengdu 610065, China;
2. School of Architecture and Environment, Sichuan University, Chengdu 610065, China

Abstract:In order to study crack dynamic propagation behavior and rock fracture toughness, single cleavage triangle (SCT) specimens were used. By using these specimens and a drop weight test system, impact experiments were performed, and the crack propagation velocity and the fracture time were measured by crack propagation gauges(CPG). In order to examine the effectiveness of the experiment results, finite difference numerical models were established by using AUTODYN. Finite element code ABAQUS was used to calculate crack dynamic stress intensity factors(SIF) based on numerical models and the measured loading curves, and the curve of crack dynamic SIF versus time was obtained. The fracture toughness was determined according to the correction universal function and the fracture time measured by CPG. The results show that the SCT specimen is suitable for the study of crack dynamic propagation behavior and fracture toughness. Propagation toughness decreases with the increase of the crack propagation velocity. The crack propagation paths obtained from numerical simulation are basically the same with those of the test results, and the crack propagation speed is not a constant. In the process of crack propagation, crack arrest may happen, in which arrest toughness is higher than crack propagation toughness, and the difference between the initiation toughness and arrest toughness is slight.

 

Key words: single cleavage triangle(SCT) specimen; dynamic initiation toughness; dynamic propagation toughness; drop weight impact; numerical simulation

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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