中心圆孔圆盘试件三维最大无量纲应力强度因子的标定

Calibration of three-dimensional maximum dimensionless stress intensity factor of holed flattened Brazilion disc specimen

基于平面假设标定的圆盘试件的无量纲应力强度因子对岩石断裂韧度的准确测定有一定的影响。使用三维断裂分析软件FRANC3D对不同中心孔尺寸的中心圆孔平台巴西圆盘HFBD试件的三维最大无量纲应力强度因子进行准确标定。结果表明:沿着圆盘厚度方向虚拟三维裂纹前缘各点的最大无量纲应力强度因子并不相等,其中心点与二维标定值最大误差接近3%,推荐了一种不受三维尺寸影响可简化为二维分析的中心圆孔平台圆盘试件尺寸。

There was a certain effect to measure accurately the rock fracture toughness with holed disc specimens, of which the maximum dimensionless of stress intensity factor was calibrated with 2D method. By three-dimensional fracture analysis software FRANC3D, the maximum dimensionless of the stress intensity factor of disc samples was calculated, which has different radius sizes of center hole. The results show that the factors on the crack the front edge along the disc thickness direction are varied, even the maximum relative error of the center point is about 3%, compared to the value made with 2D method. A type of holed flattened Brazilian disc specimen is recommend, which can be simplified to a two-dimensional problem without three-dimensional size effect.