Criterion of local symmetry visualized in small eccentric single edge notched bend (E-SENB) rock specimens
文献类型：期刊论文
| 作者 | Lin, Qing1,3; Bian, Xin1; Pan, Peng-Zhi2; Gao, Yue1; Lu, Yunhu1,3 |
| 刊名 | ENGINEERING FRACTURE MECHANICS
 |
| 出版日期 | 2021-05-01 |
| 卷号 | 248页码:21 |
| 关键词 | Criterion of local symmetry Fracture process zone (FPZ) Digital image correlation (DIC) Mixed-mode loading Fracture kink |
| ISSN号 | 0013-7944 |
| DOI | 10.1016/j.engfracmech.2021.107709 |
| 英文摘要 | Fracture criterion of local symmetry has been widely used to predict the fracture kink and simulate the fracture trajectory in rocks under the mixed-mode loading. Under small scale yielding, it must include two aspects: the local mode I stress intensity factor (SIF) kI is maximum and the local mode II SIF kII is zero. When fracture just initiates, the local kII is not zero, but it will be gradually eliminated after the crack propagates. Eventually two aspects are equivalent. Thus, a curved fracture, as a consequence from combination of the local kI and kII, already supports the criterion in reality. Once specimen size is small, the condition changes to large scale yielding such that two aspects change to: the local tensile stress is maximum and the local shear stress is zero. It poses the difficulties for the criterion, e.g., the initiated fracture is observed to keep extension after the first fracture kink, suggesting the kink angle is not sensitive to the local shear stress. To study the criterion, the eccentric single edge notched bend (E-SENB) specimens of Berea sandstone were tested and digital image correlation (DIC) was used to measure the surface displacements. DIC observations provide essential supports for two aspects: (i) the fracture initiation is dominated by opening displacements without any slips, indicating that it is the maximum value of the local tensile stress that reaches tensile strength to initiate the fracture; (ii) the challenge is about evaluation of the local shear stress, but fortunately, an interesting phenomenon provides a valuable assistance: a non-symmetric pattern of opening/orthogonal displacements. This study introduces a parameter eta, i.e., the ratio of normal displacements at two fracture sides, to quantitatively evaluate the local shear stress and its influence. Parameter eta change demonstrates the local shear influence change. For tested specimens, parameter eta is observed to decrease from a finite value of larger than 1 to 1, which suggests the local shear influence is gradually removed to be zero. Thus, criterion of local symmetry is visually validated for small E-SENB specimens. Finally, this study provides a helpful insight about the tip condition of a kinked fracture in rocks under mixed-mode loading when the condition of small scale yielding applies. |
| 资助项目 | State Key Research Development Program of China[2017YFC0804203] ; National Natural Science Foundation of China[51304225] ; National Natural Science Foundation of China[51774305] ; National Science and Technology Major Project[2016ZX05051-003] |
| WOS研究方向 | Mechanics |
| 语种 | 英语 |
| WOS记录号 | WOS:000649603200002 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| 源URL | [http://119.78.100.198/handle/2S6PX9GI/27114]  |
| 专题 | 中科院武汉岩土力学所 |
| 通讯作者 | Pan, Peng-Zhi |
| 作者单位 | 1.China Univ Petr, Coll Petr Engn, Beijing 102249, Peoples R China 2.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China 3.China Univ Petr, State Key Lab Petr Resources & Prospecting, Beijing 102249, Peoples R China |
| 推荐引用方式 GB/T 7714 | Lin, Qing,Bian, Xin,Pan, Peng-Zhi,et al. Criterion of local symmetry visualized in small eccentric single edge notched bend (E-SENB) rock specimens[J]. ENGINEERING FRACTURE MECHANICS,2021,248:21. |
| APA | Lin, Qing,Bian, Xin,Pan, Peng-Zhi,Gao, Yue,&Lu, Yunhu.(2021).Criterion of local symmetry visualized in small eccentric single edge notched bend (E-SENB) rock specimens.ENGINEERING FRACTURE MECHANICS,248,21. |
| MLA | Lin, Qing,et al."Criterion of local symmetry visualized in small eccentric single edge notched bend (E-SENB) rock specimens".ENGINEERING FRACTURE MECHANICS 248(2021):21. |
入库方式： OAI收割
来源：武汉岩土力学研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。