裂纹尺寸对混凝土断裂韧度的影响

Effect of crack size on the fracture toughness of concrete

利用断裂力学方法对含有裂纹混凝土试件的断裂韧度进行了研究。通过预制不同裂纹深度的混凝土试件,采用三点弯曲试验方法对含裂纹混凝土梁的断裂韧度进行实验,同时利用ABAQUS软件,采用最大主应力牵引损伤开裂准则与线性软化损伤模型进行数值模拟。结果表明,实验结果和数值模拟比较一致,最大误差不超过15%,当初始缝纹长度为40~120 mm时,起裂断裂韧度KiniIC变化幅度较小,失稳断裂韧度KunIC有明显的减小趋势。

The fracture toughness of concrete specimen with cracks was studied via fracture mechanic method. Through precasting concrete specimens of different crack depths, three-point ben- ding test method was employed to study the fracture toughness of the concrete beam with cracks. Meanwhile, the maximum principal stress damage and fracture criterion and linear softening damage model in the ABAQUS software were adopted to conduct the experiment. The results show that the numerical simulation result is in agreement with the experimental result with the largest difference being less than 10%, that when the initial crack length is within 40ram and 120mm, the initial fracture toughness KICini has little change while the unstable fracture toughness Kun IC is in an obvious decreasing trend.