作者：韩悌信, 曾祥国, 郭杨, 杨鑫, 陈华燕, 李洋
作者单位：四川大学建筑与环境学院, 四川 成都 610065
关键词：霍普金森杆;数值方法;NiTi合金;裂纹扩展计;动态断裂过程
摘要：
为获得NiTi合金的动态起裂韧度和动态扩展速度与动态加载率之间的定量变化规律。利用分离式霍普金森压杆（SHPB）测试系统对单边三点弯曲试样（SENB）进行冲击加载试验，采用实验-有限元相结合的方法，获得动态断裂参数随时间的变化规律。SENB试样裂纹起裂时刻和裂纹扩展速度由粘贴在裂纹尖端的裂纹扩展计（CPG）测定。采用上述方法和数据获得NiTi合金的I型动态起裂韧度和动态扩展速度。实验结果表明：裂纹扩展计测得的起裂时刻与粘贴在同一试样上的监裂应变片测得的结果基本相符，因此可以利用裂纹扩展计代替传统的监裂应变片来监测裂纹起裂时刻，并获得NiTi合金的起裂韧度。同时，可以利用裂纹扩展计（CPG）获得裂纹动态扩展过程，绘制出裂纹扩展速度与时间的关系曲线，从而探讨NiTi合金的动态断裂韧度和裂纹扩展速度与动态加载率之间的定量变化规律。
The study of experimental and numerical methods for dynamic fracture process of NiTi alloy
HAN Tixin, ZENG Xiangguo, GUO Yang, YANG Xin, CHEN Huayan, LI Yang
College of Architecture and Environment, Sichuan University, Chengdu 610065, China
Abstract: To obtain a quantitative change rule between the dynamic initial fracture toughness,dynamic crack propagation speed and dynamic loading rate of NiTi alloy,an impact loading test was conducted on single edge notched three-point bending (SENB) specimens with the split Hopkinson pressure bar (SHPB) test system based on the experimental-FEM method to figure out the variation rules of dynamic fracture parameters of NiTi alloy.The time of crack initiation and the crack extension speed were measured by the crack propagation gauge (CPG) pasted near the crack tip of the specimen.It is feasible to measure the initiation fracture toughness and crack propagation speed of Type I NiTi alloy by taking the aforementioned method.According to the test results:the crack initiation time displayed on the CPG is roughly in line with the result on the crack strain gage pasted on the same specimen.So the CPG can be used as crack strain gage,which can also measure the fracture toughness of NiTi alloy.In addition,the dynamic crack propagation process can be obtained with the CPG.According to the dynamic crack propagation process,the relation curve between crack propagation speed and time can be drawn out.In this way,the quantitative change rule between the dynamic fracture toughness,dynamic crack propagation speed and dynamic loading rate of NiTi alloy can be worked out.
Keywords: SHPB system;numerical method;NiTi alloy;crack propagation gauge;dynamic fracture process
2016, 42(10): 72-78 收稿日期: 2016-4-10;收到修改稿日期: 2016-5-25
基金项目: 国家自然科学委员会与中国工程物理研究院联合基金项目（U1430119）
作者简介: 韩悌信(1991-),男,甘肃兰州市人,硕士研究生,专业方向为材料疲劳与破坏。
参考文献
[1] 阚前华,康国政,钱林茂,等. 超弹性NiTi合金相变棘轮行为的实验研究[J]. 金属学报,2008,44(8):949-955.
[2] TANAKA K, KAGATSUME T. Impact bend test on steel at low temperatures using a split Hopkinson bar[J]. Bulletin of the Seismological Socierty of America,1980,185(23):1736-1744.
[3] BERGER J R, DALLY J W, DEWIT R, et al. Strain gage analysis of fracture in wide plate tests of reactor grade steel[J]. Journal of Pressure Vessel Technology,1993,115(4):112-117.
[4] 李玉龙,刘元镛. 用弹簧质量模型求解三点弯曲试样的动态应力强度因子[J]. 固体力学学报,1994(1):75-79.
[5] 张晓欣,刘瑞堂. 某船用钢动态弹塑性断裂韧性的试验测试[J]. 实验力学,2002,17(2):153-159.
[6] 杨井瑞,张财贵,周妍,等. 用SCDC试样测试岩石动态断裂韧度的新方法[J]. 岩石力学与工程学报,2015,34(2):279-292.
[7] 陈华燕,曾祥国,李星,等. 利用实验和数值结合的方法测量镁合金AZ91动态断裂韧性[J]. 四川大学学报(工程科学版),2013,45(6):149-152.
[8] XU T, STEWART R, FAN J, et al. Bridging Crack Propagation at the Atomistic and Mesoscopic Scale for BCC-Fe with Hybrid Multiscale Methods[J]. Engineering Fracture Mechanics,2016(155):166-182.
[9] PEI L, LU C, TIEU K, et al. Ductile-to-brittle fracture transition in polycrystalline nickel under tensile hydrostatic stress[J]. Computational Materials Science,2015(109):147-156.
[10] 刘德顺,李夕兵. 冲击机械动力学与反演设计[M]. 北京:科学出版社,1999:30-31.
[11] 卢芳云. 霍普金森杆实验技术[M]. 北京:科学出版社,2013:236-237.
[12] RICE J R. A path 2 independence integral and the approximate a analysis of strain concentration by notches and cracks[J]. JAppl Mech,1968(35):376-386.
[13] 雷和荣,虞吉林. 虚裂纹扩展法计算J积分的研究[J]. 中国科学技术大学学报,1994,24(2):207-213.
[14] KISHIMOTO K, AOKI S, SAKATA M. Dynamic stress intensity factors using J-integral and finite elements method[J]. Eng Fract Mech,1980(13):387-394.
[15] NISHIOKA T, ATLURI S N. Path 2 independent integrals, energy release rates and general solutions of near-tip fields in mixed-mode dynamic fracture mechanics[J]. Eng Fract Mech,1983(18):1-22.
