预制裂缝宽度对变尺寸圆盘试样应力强度因子的影响

Research on the influence of prefabricated crack width for the stress intensity factor of variable size disc specimens

为研究了预制裂缝宽度对不同尺寸圆盘试样无量纲应力强度因子的影响,采用ABAQUS有限元软件,对圆盘直径分别为40,80,100,120,200 mm,预制裂缝宽度0~2.0 mm内的直裂缝平台巴西圆盘试样进行数值分析,基于等效区域积分法标定了在裂缝长度与圆盘直径比为0.55条件下的无量纲应力强度因子。结果表明,在圆盘直径一定条件下,无量纲应力强度因子随着裂缝宽度增加而增加,最大相对误差为13.53%;随着圆盘直径增大,预制裂缝宽度带来的影响相对减弱,但最大相对误差仍然超过3%。给出了消除预制裂缝宽度影响的无量纲应力强度因子修正公式,为采用含有预制裂缝的圆盘试样准确确定岩石的断裂韧度提供理论支持。

In order to get the influence of prefabricated crack width on the dimensionless stress intensity of disc specimen with different sizes. ABAQUS software was used for,numerical analysis of cracked straight-through flattened Brazilian disc(CSTFBD). In the model,the sizes of disc diameter were 40 mm,80 mm,100 mm,120 mm and 200 mm and the width of prefabricated crack ranged from 0 mm to 2. 0 mm. The dimensionless stress intensity factors were calibrated by the equivalent zone integration method when the ratio of crack length to disc diameter was 0. 55. Results show that the dimensionless stress intensity increase along with the increase of the crack width. The maximum relative error is 13. 53 % when the disc specimens have same diameter sizes. If the size of disc diameter increase,the influence will be decreased,however the maximum relative error is still more than 3 %. A revised formula of the dimensionless stress intensity factor was given to eliminate the influence of the prefabricated crack width. It provides a theoretical basis for determining the fracture toughness value by using cracked straight-through flattened Brazilian disc specimen.