混凝土冲击拉伸力学性能及裂纹扩展试验研究和数值模拟  

Experimental Study and Numerical Simulation of Split Tensile Properties and Crack Propagation of Concrete

作　　者：戚亚珍 张华[1] 郭继鑫 Qi Yazhen, Zhang Hua ,Guo Jixin(College of Civil ＆. Transportation Engineering, Hohai Univ. , Nanjing 210098, Chin)

机构地区：[1]河海大学土木与交通学院,南京210098

出　　处：《三峡大学学报（自然科学版）》2018年第3期56-60,共5页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金青年基金(51609071);江苏省自然科学基金青年基金(BK20140848)

摘　　要：为真实反映混凝土材料劈裂拉伸力学性能,基于应变片法采用分离式霍普金森压杆对混凝土平台巴西圆盘试件进行了劈裂拉伸试验,研究了不同加载角对试件起裂方式及破坏模式的影响,并对试件破坏过程进行了扩展有限元模拟,同时与试验结果进行了对比分析,得到用于测试混凝土拉伸力学性能的最优加载角.基于此得到动态劈拉下3种不同强度混凝土的劈裂拉伸应力-径向应变曲线及抗拉强度、极限应变、拉伸敏感系数等参数的应变率效应.结果表明:20°加载角可以保证圆盘在中心起裂,用于测试混凝土劈裂拉伸性能最为可靠.在高应变率下,混凝土动态力学参数均具有明显的应变率效应,裂纹沿试件受力方向扩展、贯通直至试件沿加载直径方向劈裂为两半,破坏面表现为骨料破坏,与数值模拟结果一致.For the real split tensile properties of concrete, the splitting tensile test of the Brazilian disc specimen is carried out by using the split Hopkinson pressure bar（SHPB） based on the strain gauge method. Theeffects of different loading angles on the failure mode are studied and the finite element simulation of the failure process of the specimen is carried out. The effect of loading angle on the crack propagation and the failuremechanism of concrete are studied. What＇s more, the split tensile stress radial strain curve is got; and thestrain rate effect of the tensile strength, ultimate strain and tensile sensitivity coefficient are analyzed. The results show that the loading angle of 20° can ensure the specimens crack at the center; and it is the most reliable to test the splitting tensile properties of concrete. Under the high strain rate, the dynamic parameters ofconcrete have obvious strain rate effect; the crack propagates along the loading direction; and the specimen issplit into two parts with a certain width of shear zone; and the failure surface shows an aggregate destruction.The numerical simulation results are consistent with the experimental results.

关 键 词：霍普金森压杆 加载中心角 平台巴西圆盘 裂纹扩展 力学性能 扩展有限元 

分 类 号：TU528[建筑科学—建筑技术科学]