【摘要】 采用LS-DYNA有限元软件,对含中心裂纹的岩石巴西圆盘试件在冲击压缩荷载作用下的变形过程进行数值分析。基于虚拟裂纹闭合技术,提出在冲击载荷作用下裂纹结构能量释放率和动态应力强度因子的计算方法,得到巴西盘试件的能量释放率和应力强度因子与时间的关系曲线,并给出不同冲击速率对该曲线的影响。对含中心裂纹的岩石巴西盘试件在冲击压缩荷载作用下I型断裂参数与II型断裂参数的时间历程曲线进行比较。计算结果表明:在相同冲击速度下,在同一时刻II型断裂参数的数值比I型断裂参数小几个量级,含中心裂纹的巴西盘试件可作为I型断裂模型处理。更多还原

【Abstract】 The finite element commercial code LS-DANA is used to study the deformation process of Brazilian disk with pre-existing crack under impact loading.According to the virtual crack closure technique(VCCT),the calculation methods for energy release rate and stress intensity factor are developed for impact loading.The variations of energy release rate and stress intensity factor with time are obtained.The effects of impact velocities on energy release rate and stress intensity factor are also analyzed.A comparison between fracture parameters for model I and model II shows that the parameters of model II are much smaller than those of model I.The Brazilian disk with a pre-existing center crack could be regarded as model I crack problem.更多还原