K_(Ⅰ)和K_(Ⅱ)型等值条件下Ⅱ型断裂对Ⅰ型断裂韧性值的干扰效应  

Interference effect of type-Ⅱ fracture on the value of type-Ⅰ fracture toughness when K_(Ⅰ)=K_(Ⅱ)

作　　者：邓友生[1] 李龙[1] DENG You-sheng;LI Long(College of Civil and Architectural Engineering,Xi’an University of Science and Technology,Xi’an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054

出　　处：《佛山科学技术学院学报（自然科学版）》2021年第5期1-10,共10页Journal of Foshan University(Natural Science Edition)

摘　　要：利用奇异应力边界多裂纹开裂的几何模型,研究了K_(Ⅰ)和K_(Ⅱ)型等值条件下Ⅱ型断裂对Ⅰ型断裂韧性值的干扰效应。基于能量释放率与裂纹分叉理论,引入扰动系数ε建立多裂纹能量释放率模型,对比不同ε对能量型开裂驱动力的影响,同时结合断裂力学中的J积分理论,分析、量化了扰动效应,给出了受Ⅱ型弱载荷影响的潜在Ⅰ型裂纹扩展的断裂准则,并与有限元结果进行对比。研究表明,等值条件下干扰系数ε在0.317%~0.438%之间,说明在Ⅰ型断裂韧性值测试过程中受到微弱Ⅱ型断裂的影响;随着分析步逐渐增加,干扰系数ε减小,说明断裂韧性值测试过程中干扰效应逐渐减弱;量化了Ⅱ型弱载荷Ⅰ型断裂韧性测试中的干扰效应,有助于更好地分析实验过程中分散的测量数据,为复杂裂纹的边翼分叉和偏折研究提供新思路。The interference effect of type-Ⅱ fracture on the value of type-Ⅰ fracture toughness when K_(Ⅰ)=K_(Ⅱ) were studied based on the geometrical modeling for stress singularity boundary multi-direction cracking. Based on the energy release rate and crack bifurcation theory, the disturbance coefficient ε is introduced to establish a multi-crack energy release rate model, and the influence of different ε on the driving force of energy-type cracking is compared. At the same time, combined with the J integral theory in fracture mechanics, the disturbance effect is analyzed and quantified. The fracture criterion of potential type Ⅰ crack propagation affected by type Ⅱ weak load is given and compared with the finite element results. Studies have shown that the interference coefficient ε is between 0.317% and 0.438% under the equivalent conditions, indicating that the type Ⅰ fracture toughness value test is affected by weak type Ⅱ fractures;as the analysis step gradually increases,the interference coefficient ε decreases. It shows that the interference effect is gradually weakened during the fracture toughness test;the interference effect in the type Ⅱ weak load type Ⅰ fracture toughness test is quantified,which is helpful to better analyze the scattered measurement data in the experimental process, and provides a new idea for the study of edge and wing bifurcation and deflection of complex cracks.

关 键 词：断裂韧性 裂纹 能量释放率 扰动效应 Ⅰ型裂纹 

分 类 号：O346.1[理学—固体力学]