Abstract: The effect of fulcrum friction on the composite fracture behavior of semi-circular bend (SCB) specimens I-II under the condition of fixed support was studied. Considering factors such as fracture inclination, fracture length, fulcrum span and friction coefficient of fulcrum, a numerical model of 200 SCB specimens was established by ABAQUS numerical analysis software, The mode I(II) dimensionless strength factor YⅠ(YⅡ) and dimensionless T stress T* of SCB sample were calibrated. The numerical results show that the values of Y, YYⅡ and T* decrease to different degrees when the fulcrum friction is taken into account. The friction coefficients of the fulcrum can significantly change the loading mode of the fracture tip, resulting in a decrease in the angle (βⅡ) of the loading mode reaching pure mode II.

摘要： 研究固定支座条件下，支点摩擦对半圆弯曲（SCB）试样I-II复合型断裂行为的影响。考虑裂缝倾角、裂缝长度、支点跨距和支点摩擦系数等因素，采用ABAQUS数值分析软件建立了200个SCB试样的数值模型，对SCB试样的Ⅰ型、Ⅱ型无量纲应力强度因子YⅠ、YⅡ以及无量纲T应力、T*进行了标定。数值结果表明：考虑支点摩擦后YⅠ、YⅡ、T*数值发生了不同程度的减小。支点摩擦系数可以显著改变裂缝尖端的加载模式，会导致加载模式达到纯Ⅱ型的角度βⅡ减小。