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| 三点弯曲型试件Ⅰ/Ⅱ复合型断裂的数值与实验研究 |
| Numerical simulation and experimental study of three-point bending specimen's Ⅰ/Ⅱ mixed mode fracture |
| Received:February 24, 2017 Revised:April 04, 2017 |
| DOI：10.7520/1001-4888-17-040 |
| 中文关键词: 三点弯曲 数值分析 砂岩 复合型断裂 |
| 英文关键词:three-point bending numerical analysis sandstone mixed mode fracture |
| 基金项目:四川省科技计划(编号2018JY0024);国家重大科研仪器设备研制专项(编号11327801) |
| Author Name | Affiliation | | LI Yi-fan | College of Architecture and Environment, Sichuan University, Chengdu 610065, China | | DONG Shi-ming* | College of Architecture and Environment, Sichuan University, Chengdu 610065, China | | LI Kun-yun | College of Architecture and Environment, Sichuan University, Chengdu 610065, China | | HUA Wen | College of Architecture and Environment, Sichuan University, Chengdu 610065, China |
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| 中文摘要: |
| 三点弯曲试件常被用来研究材料的纯Ⅰ型及Ⅰ/Ⅱ复合型断裂性能。使用Abaqus软件通过有限元法获得三点弯曲试件不同跨长比2S/L、相对裂纹长度a和裂纹倾角β下的Ⅰ型与Ⅱ型无量纲应力强度因子。由有限元结果可知，在相对裂纹长度一定时，跨长比越小,裂纹倾角越小，Ⅰ型无量纲应力强度因子可取得0，即越容易得到纯Ⅱ型断裂。当跨长比相同时，相对裂纹长度越大越容易得到纯Ⅱ型断裂。使用6组共24个三点弯曲试件，研究砂岩的纯Ⅰ型、纯Ⅱ型以及复合型加载时的断裂韧度，得到该种砂岩的纯Ⅰ型断裂韧度为0.786MPa\5m0.5，纯Ⅱ型断裂韧度为0.344MPa\5m0.5。实验结果与最大周向应力(MTS)准则和广义最大周向应力(GMTS)准则的预测结果进行对比，比较结果显示GMTS准则更能准确地预测实验结果。 |
| 英文摘要: |
| Three point bending specimens are often used to study the pure mode Ⅰ and Ⅰ/Ⅱ mixed mode fracture properties of materials. By using Abaqus finite element method, both mode Ⅰ and mode Ⅱ dimensionless stress intensity factors of three point bending specimens with different span length ratios 2S/L, relative crack length α and crack inclination angle β were obtained. It will be seen from this that when the relative crack length is constant, if span length ratio is smaller, the crack inclination angle will also be smaller, mode Ⅰ dimensionless stress intensity factor can be 0, which means it is easier to get pure mode Ⅱ fracture. When the span length ratio is the same, the greater the relative crack length α is, the easier to get pure mode Ⅱ fracture. A total 6 groups of 24 three point bending specimens were adopted to experimentally study pure mode Ⅰ, pure mode Ⅱ and mixed mode fracture toughness of sandstone. The pure mode Ⅰ fracture toughness of this kind of sandstone is 0.786MPa ·m0.5, and the pure mode Ⅱ fracture toughness is 0.344MPa·m0.5, respectively. Experimental results were compared with prediction results from maximum circumferential stress (MTS) criterion and generalized maximum circumferential stress criterion (GMTS) respectively. Comparison shows that the GMTS criterion can predict more accurate experimental results. |
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