分布载荷加载下中心直裂纹巴西圆盘的断裂参数研究

Analytical study of fracture parameters for a centrally cracked Brazilian disc subjected to distributed diametral pressures

为研究分布载荷加载对中心直裂纹巴西圆盘试样断裂参数的影响,综合运用复变函数理论及权函数方法,在推导出5种形式分布载荷加载下中心直裂纹巴西圆盘(简称CCBD)试样的任意I-II型断裂参数解析解的基础上探究接触载荷分布形式及分布角度对I、II型应力强度因子及T应力的影响。研究结果表明:当接触载荷的分布角度及裂纹相对长度较大时,接触载荷的分布形式对几何参数YI、YII及T^(*)的影响较显著;纯I型断裂的YI、T^(*)及纯II型断裂的YII均随接触载荷分布角度的增大而减小,而纯II型断裂的T^(*)却随接触角度的增大而增大;当接触载荷形式为常数函数时,载荷分布角度对几何参数的影响最大,而四次函数下,载荷分布角度对几何参数的影响相对最小;纯II型断裂角度受接触载荷分布形式及分布角度影响较小,而中心裂纹相对长度对其影响较显著。

To investigate the effects of distributed diametral pressures on fracture parameters of a centrally cracked Brazilian disc(CCBD) specimen, the complex potentials theory and weight function method were adopted to derive the mixed-mode I/II fracture parameters of CCBD specimens subjected to five types of distributed loads. Based on the analytical solutions for fracture parameters,the effects of pressure distribution form and pressure distribution angle on stress intensity factors under mode I/II and T stress were investigated. The results show that the pressure distribution form has a remarkable influence on the geometric parameters, YI, YII and T^(*), with the relatively larger pressure distribution angle and crack length. The YI and T^(*) under pure mode I and the YII under pure mode II both decrease as the pressure distribution angle increases, while the T^(*) under pure mode II increases with an increased pressure distribution angle. When the pressure distribution form is a constant function, the pressure distribution angle has the most obvious effect on geometric parameters, while the degree of the influence reduces greatly for quartic polynomial function. The critical fracture angle under pure mode II is less affected by the pressure distribution form and pressure distribution angle, while the crack length has a significant effect on it.