基于数字散斑方法的花岗岩断裂力学特性研究

Study on Fracture Mechanics Characteristics of Granite Based on DIC Technique

基于数字散斑(DIC)相关方法,进行了含预制裂纹花岗岩矩形梁三点弯曲实验,得到了其Ⅰ型裂纹断裂韧度,分析了试样破坏的全场位移和应变及其随时间的演化规律.提出了应变达到0.4%的位置为高应力区来确定过程区尖端的方法,并依据此方法来计算过程区尖端的扩展速度.结果表明,利用数字散斑相关方法能够定量计算实验过程中过程区的扩展及其速度,该速度随过程区的扩展呈加速趋势.

Based on the digital image correlation（DIC）technique,modeⅠfracture toughness of granite was obtained through three-point bending tests of rectangular beam with pre-crack.The evolution laws of displacement field and strain field were analyzed when the specimens were cracking.The method of determining the tip of the process zone by using the high stress area where the strain teaches 0.4%is proposed.Based on this method,the speed of the tip of process zone is calculated.The results show that the extension of the process zone and its speed during the experiment can be quantitatively calculated by the digital speckle correlation method,and the velocity accelerates with the extension of the process zone.