中心直裂纹平台巴西圆盘复合型动态断裂实验研究  

Experimental Study of Mixed Mode Dynamic Fracture for Cracked Straight Through Flattened Brazilian Disc

作　　者：汪坤[1] 王启智[1] 

机构地区：[1]四川大学土木工程及应用力学系,成都610065

出　　处：《实验力学》2008年第5期417-426,共10页Journal of Experimental Mechanics

基　　金：国家自然科学基金项目(10472075);中科院山地所开放基金项目(2007)

摘　　要：制作了中心直裂纹平台巴西圆盘(cracked straight through flattened Brazilian disc-CSTFBD)试样,利用分离式霍普金森压杆(split Hopkinson pressure bar SHPB)加载,进行了岩石纯Ⅰ型和复合型(Ⅰ+Ⅱ型)动态断裂实验。由于加载角(载荷方向与裂纹线的夹角)在制作试样时已经通过裂纹线与试样平台的位置关系确定,因此在实验中可以方便而准确地实施加载。比较了纯Ⅰ型加载和复合型加载下压杆上记录的入射波、反射波和透射波的波形。采用实验与数值相结合的方法,将实验得到的动态载荷输入有限元程序,得到了纯Ⅰ型试样的动态断裂韧度和复合型试样的两种动态应力强度因子的时间历程。计算了加载角为15°的试样应力强度因子的复合比(KⅠ(t)/KⅡ(t)),此计算值与文献结果吻合较好,验证了实验方法的有效性。Cracked straight through flattened Brazilian disc （CSTFBD） specimens were prepared for mode I and Ⅰ＋Ⅱ mixed mode dynamic fracture tests, which were loaded by split Hopkinson pressure bar （SHPB）. The loading angle was predetermined by the relationship between the loading direction and the crack line, so that the specimens could be loaded conveniently and accurately. The incident wave, reflected wave and transmission wave in the bars were compared respectively between mode Ⅰ test and Ⅰ＋Ⅱ mixed mode test. The dynamic load history was obtained from the test, which was inputted to the finite element analysis to calculate the dynamic stress intensity factor for mixed mode specimen and dynamic fracture toughness for mode I specimen. The mixed mode stress intensity factor ratio （KI （t）/KⅡ （t）） with 15° loading angle was also calculated and compared with the value adopted from references. Favorable agreement between them shows the validity of experimental method presented in this paper.

关 键 词：中心直裂纹平台巴西圆盘 分离式霍普金森压杆 复合型动态断裂 动态断裂韧度 

分 类 号：O346.4[理学—固体力学] O347.3[理学—力学]