一种基于SHTB的Ⅱ型动态断裂实验技术
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摘要
冲击剪切载荷作用下动态断裂韧性的测定是材料力学性能和断裂行为研究中重要组成部分.为了测定材料的Ⅱ型动态断裂韧性,许多学者采用不同的试样与实验方法进行了实验,但限于实验条件,裂纹断裂模式往往是I+Ⅱ复合型,而不是纯Ⅱ型,因而不能准确测得材料的Ⅱ型动态断裂韧性.鉴于此,本文基于分离式霍普金森拉杆(split Hopkinson tension bar,SHTB)实验技术,提出一种改进的紧凑拉伸剪切(modified compact tension shear,MCTS)试样,通过夹具对MCTS试样施加约束,从而保证试样按照纯Ⅱ型模式断裂.采用实验-数值方法对MCTS试样动态加载过程进行分析,将实验测得的波形输入有限元软件ANSYS-LSDYNA,得到了裂纹尖端应力强度因子-时间曲线,并与紧凑拉伸剪切(compact tension shear,CTS)试样进行了对比.同时采用数字图像相关法进行了实验,验证了有限元分析结果.结果表明,MCTS试样在整个加载过程中K_I K_Ⅱ,裂纹没有张开;而CTS试样在同样的加载过程中K_I>K_Ⅱ,出现裂纹张开现象.这说明MCTS试样能够准确地测定材料的Ⅱ型动态断裂韧性,为材料动态力学测试提供了一种有效的实验技术.
Dynamic fracture toughness under impact shear loading is an essential aspect in fracture behavior and mechanical property of material. Experiments have been done by several researchers using different specimens and test methods in order to measure mode Ⅱ fracture toughness. But due to crack opening during loading process, the results obtained in these tests are not mode Ⅱ but mixed mode I+Ⅱ. Since crack opening are not be considered, dynamic shear fracture toughness of material can not be accurately detected. In view of this problem, a modified compact tension shear(MCTS)specimen based on split Hopkinson tension bar(SHTB) apparatus is proposed in this paper. The specimen was constrained with special designed clamp to prevent crack opening, so mode Ⅱ fracture are ensured. Numerical analysis was carried out using experimental-numerical method. The incident pulse detected in test are introduced in ANSYS-LSDYNA as input pulse. Stress intensity factor at crack tip of MCTS specimen was calculated by relative displacement of corresponding nodes on crack surface in two directions. Simulation of compact tension shear(CTS) specimen was also done with same incident pulse as control. In addition, experimental study was also carried out using digital image correlation method based on SHTB apparatus to validate numerical results. Experimental results shows that during loading process, MCTS specimen ensures K_I K_Ⅱ and crack opening are not observed. However, for same incident pulse, the maximum mode I stress intensity factor of CTS specimen is even higher than mode Ⅱ. Which indicates that dynamic shear fracture toughness of material can be measured effectively using MCTS specimen. This work provides an effective and convenient test technique for evaluating dynamic properties of a certain material.
Dynamic fracture toughness under impact shear loading is an essential aspect in fracture behavior and mechanical property of material. Experiments have been done by several researchers using different specimens and test methods in order to measure mode Ⅱ fracture toughness. But due to crack opening during loading process, the results obtained in these tests are not mode Ⅱ but mixed mode I+Ⅱ. Since crack opening are not be considered, dynamic shear fracture toughness of material can not be accurately detected. In view of this problem, a modified compact tension shear(MCTS)specimen based on split Hopkinson tension bar(SHTB) apparatus is proposed in this paper. The specimen was constrained with special designed clamp to prevent crack opening, so mode Ⅱ fracture are ensured. Numerical analysis was carried out using experimental-numerical method. The incident pulse detected in test are introduced in ANSYS-LSDYNA as input pulse. Stress intensity factor at crack tip of MCTS specimen was calculated by relative displacement of corresponding nodes on crack surface in two directions. Simulation of compact tension shear(CTS) specimen was also done with same incident pulse as control. In addition, experimental study was also carried out using digital image correlation method based on SHTB apparatus to validate numerical results. Experimental results shows that during loading process, MCTS specimen ensures K_I K_Ⅱ and crack opening are not observed. However, for same incident pulse, the maximum mode I stress intensity factor of CTS specimen is even higher than mode Ⅱ. Which indicates that dynamic shear fracture toughness of material can be measured effectively using MCTS specimen. This work provides an effective and convenient test technique for evaluating dynamic properties of a certain material.
引文
1 Blackman B,Kinloch A,Wang Y,et al.The failure of fibre composites and adhersively bonded fibre composites under high rates of test.Journal of Material Science,1996,31(17):4451-4466
2 Blackman B,Kinloch A,Ro driguez-Sanchez FS,et al.The fracture behavior of adhersively bonded composite joints:Effects of rate of test and mode of loading.International Journal of Solid and Structures,2012,49(13):1434-1452
3 Todo M,Nakamura T,Takashi K.Mode II interlaminar fracture behavior of fiber reinforced polyamide composites under static and dynamic loading conditions.Journal of Reinforced Plastics and Composites,1999,18(15):1415-1427
4 Todo M,Nakamura T,Mada T,et al.Measurement of dynamic interlaminar fracture toughness of FRP laminates using dynamic displacement measuring apparatus.Advanced Composite Materials,1998,7(3):285-297
5 Iqbal MA,Senthil K,Sharma P,et al.An investigation of the constitutive behavior of Armox 500T steel and armor piercing incendiary projectile material.International Journal of Impact Engineering,2016,96:146-164
6许泽建,丁晓燕,张炜琪等.一种用于材料高应变率剪切性能测试的新型加载技术.力学学报,2016,48(3):654-659(Xu Zejian,Ding Xiaoyan,Zhang Weiqi,et al.A new loading technique for measuring shearing properties of materials under high strain rates.Chinese Journal of Theoretical and Applied Mechanics,2016,48(3):654-659(in Chinese))
7于金程,刘正,董阳等.高应变速率下Mg-Gd-Y镁合金动态拉伸性能与失效行为.沈阳工业大学学报,2015,37(6):650-655(Yu Jincheng,Liu Zheng,Dong Yang,et al.Dynamic tensile properties and failure behavior of Mg-Gd-Y alloy at high strain rates.Journal of Shenyang University of Technology,2015,37(6):650-655(in Chinese))
8邹广平,沈昕慧,赵伟玲等.SHTB加载紧凑拉伸试样断裂韧性测试仿真.哈尔滨工程大学学报,2015,36(7):917-921(Zou Guangping,Shen Xinhui,Zhao Weiling,et al.Numerical simulation of dynamic fracture toughness tests on the compact tension specimen loaded by SHTB.Journal of Harbin Engineering University,2015,36(7):917-921(in Chinese))
9 Xia KW,Yao W.Dynamic rock tests using split Hopkinson(Kolsky)bar system-A review.Journal of Rock Mechanics and Geotechnical Engineering,2015,7(1):27-59
10李玉龙,刘会芳.加载速率对层间断裂韧性的影响.航空学报,2015,36(8):2620-2650(Li Yulong,Liu Huifang.Loading rate effect on interlaminar fracture toughness.Acta Aeronautica et Astronautica Sinica,2015,36(8):2620-2650(in Chinese))
11 Kusaka T,Hojo M,Mai YW,et al.Rate dependence of mode Ifracture behavior in carbon-fiber/epoxy composite laminates.Composite Science and Technology,1998,58(3-4):591-602
12 Kusaka T,Kurokawa T,Hojo M,et al.Evaluation of mode II interlaminar fracture composite of laminates under impact loading.Key Engineering Materials,1997,141-143:477-500
13 Kusaka T,Yamaguchi Y,Kurokawa T.Effect of strain rates on mode II interlaminar fracture toughness in carbon-fiber/epoxy laminated composites.Journal of Physics IV France,1994,4(8):671-676
14 Jiang F,Vecchio KS.Hopkinson bar loaded fracture experimental technique:A critical review of dynamic fracture toughness tests.Applied Mechanics Reviews,2009,62(6):1-39
15 Yokoyama T,Kishida K.A novel impact three-point bend test method for determining dynamic fracture initiation toughness.Experimental Mechanics,1989,29(2):188-194
16 Rubio L,Fernandez-Saze J,Navarro C.Determination of dynamic fracture initiation toughness using three-point bending tests in a modified Hopkinson pressure bar.Experimental Mechanics,2003,43(2):379-386
17 Lambros J,Rosakis AJ.Dynamic crack initiation and growth in thick unidirectional graphite/epoxy plates.Composite Science and Technology,1997,57(1):413-421
18 Wu XF,Dzenis YA.Determination of dynamic delamination toughness of a graphite-fiber/epoxy composite using Hopkinson bar.Polymer Composites,2005,26(2):165-180
19 Sohn MS,Hu XZ.Impact and high strain rate delamination characteristics of carbon fiber epoxy composites.Theoretical and Applied Fracture Mechanics,1996,25(1):17-29
20 Wen X,Lu F,Chen R,et al.Experimental studies on mixed-mode dynamic fracture behaviour of aluminium alloy plates with narrow U-notch.Fatigue and Fracture of Engineering Materials and Structures,2016,39(11):1379-1390
21沈昕慧.应力波加载下材料动态断裂韧性相关实验技术研究.[博士论文].哈尔滨:哈尔滨工程大学,2016(Shen Xinhui.Investigation on dynamic fracture toughness experimental technique under stress wave load.[Ph D Thesis].Harbin:Harbin Engineering University,2016(in Chinese))
22 Richard HA.A new compact shear specimen.International Journal of Fracture,1981,17(5):105-107
23 Anderson TL.Fracture Mechanics,Foundations and Applications.Boca Raton,CRC Press,1991
24王自强,陈少华.高等断裂力学.北京:科学出版社,2009:43-76(Wang Ziqiang,Chen Shaohua.Advanced Fracture Mechanics.Beijing:Science Press,2009:43-76(in Chinese))
25 Xu Z,Li Y.A novel method in determination of dynamic fracture toughness under mixed mode I/II impact loading.International Journal of Solids and Structures,2012,49:366-376
26郦正能.应用断裂力学.北京:北京航空航天大学出版社,2012:64-72(Li Zhengneng.Applied Fracture Mechanics.Beijing:Beihang University Press,2012:64-72(in Chinese))
27 Peters WH,Ranson WH.Digital imaging technique in experimental mechanics.Opt Eng,1982,21(3):427-431
28 Yamaguchi I.Speckle displacement and deformation in the diffraction and image fields for small object deformation.Opt Acta,1981,28(10):1359-1376
29周忠彬,陈鹏万,黄风雷.PBX材料宏细观断裂行为的数字散斑相关法实验研究.高压物理学报,2011,25(1):1-7(Zhou Zhongbin,Chen Pengwan,Huang Fenglei.An experimental study on the micro/macro fracture behavior of PBX using digital speckle correlation method.Chinese Journal of High Pressure Physics,2011,25(1):1-7(in Chinese))
30邹广平,汪艳伟,唱忠良等.基于数字散斑相关法的紧凑拉伸试样断裂韧性实验研究.实验力学,2015,30(3):275-281(Zou Guangping,Wang Yanwei,Chang Zhongliang,et al.Experimental study of compact tension specimen fracture toughness based on digital speckle correlation method.Journal of Experimental Mechanics,2015,30(3):275-281(in Chinese))
2 Blackman B,Kinloch A,Ro driguez-Sanchez FS,et al.The fracture behavior of adhersively bonded composite joints:Effects of rate of test and mode of loading.International Journal of Solid and Structures,2012,49(13):1434-1452
3 Todo M,Nakamura T,Takashi K.Mode II interlaminar fracture behavior of fiber reinforced polyamide composites under static and dynamic loading conditions.Journal of Reinforced Plastics and Composites,1999,18(15):1415-1427
4 Todo M,Nakamura T,Mada T,et al.Measurement of dynamic interlaminar fracture toughness of FRP laminates using dynamic displacement measuring apparatus.Advanced Composite Materials,1998,7(3):285-297
5 Iqbal MA,Senthil K,Sharma P,et al.An investigation of the constitutive behavior of Armox 500T steel and armor piercing incendiary projectile material.International Journal of Impact Engineering,2016,96:146-164
6许泽建,丁晓燕,张炜琪等.一种用于材料高应变率剪切性能测试的新型加载技术.力学学报,2016,48(3):654-659(Xu Zejian,Ding Xiaoyan,Zhang Weiqi,et al.A new loading technique for measuring shearing properties of materials under high strain rates.Chinese Journal of Theoretical and Applied Mechanics,2016,48(3):654-659(in Chinese))
7于金程,刘正,董阳等.高应变速率下Mg-Gd-Y镁合金动态拉伸性能与失效行为.沈阳工业大学学报,2015,37(6):650-655(Yu Jincheng,Liu Zheng,Dong Yang,et al.Dynamic tensile properties and failure behavior of Mg-Gd-Y alloy at high strain rates.Journal of Shenyang University of Technology,2015,37(6):650-655(in Chinese))
8邹广平,沈昕慧,赵伟玲等.SHTB加载紧凑拉伸试样断裂韧性测试仿真.哈尔滨工程大学学报,2015,36(7):917-921(Zou Guangping,Shen Xinhui,Zhao Weiling,et al.Numerical simulation of dynamic fracture toughness tests on the compact tension specimen loaded by SHTB.Journal of Harbin Engineering University,2015,36(7):917-921(in Chinese))
9 Xia KW,Yao W.Dynamic rock tests using split Hopkinson(Kolsky)bar system-A review.Journal of Rock Mechanics and Geotechnical Engineering,2015,7(1):27-59
10李玉龙,刘会芳.加载速率对层间断裂韧性的影响.航空学报,2015,36(8):2620-2650(Li Yulong,Liu Huifang.Loading rate effect on interlaminar fracture toughness.Acta Aeronautica et Astronautica Sinica,2015,36(8):2620-2650(in Chinese))
11 Kusaka T,Hojo M,Mai YW,et al.Rate dependence of mode Ifracture behavior in carbon-fiber/epoxy composite laminates.Composite Science and Technology,1998,58(3-4):591-602
12 Kusaka T,Kurokawa T,Hojo M,et al.Evaluation of mode II interlaminar fracture composite of laminates under impact loading.Key Engineering Materials,1997,141-143:477-500
13 Kusaka T,Yamaguchi Y,Kurokawa T.Effect of strain rates on mode II interlaminar fracture toughness in carbon-fiber/epoxy laminated composites.Journal of Physics IV France,1994,4(8):671-676
14 Jiang F,Vecchio KS.Hopkinson bar loaded fracture experimental technique:A critical review of dynamic fracture toughness tests.Applied Mechanics Reviews,2009,62(6):1-39
15 Yokoyama T,Kishida K.A novel impact three-point bend test method for determining dynamic fracture initiation toughness.Experimental Mechanics,1989,29(2):188-194
16 Rubio L,Fernandez-Saze J,Navarro C.Determination of dynamic fracture initiation toughness using three-point bending tests in a modified Hopkinson pressure bar.Experimental Mechanics,2003,43(2):379-386
17 Lambros J,Rosakis AJ.Dynamic crack initiation and growth in thick unidirectional graphite/epoxy plates.Composite Science and Technology,1997,57(1):413-421
18 Wu XF,Dzenis YA.Determination of dynamic delamination toughness of a graphite-fiber/epoxy composite using Hopkinson bar.Polymer Composites,2005,26(2):165-180
19 Sohn MS,Hu XZ.Impact and high strain rate delamination characteristics of carbon fiber epoxy composites.Theoretical and Applied Fracture Mechanics,1996,25(1):17-29
20 Wen X,Lu F,Chen R,et al.Experimental studies on mixed-mode dynamic fracture behaviour of aluminium alloy plates with narrow U-notch.Fatigue and Fracture of Engineering Materials and Structures,2016,39(11):1379-1390
21沈昕慧.应力波加载下材料动态断裂韧性相关实验技术研究.[博士论文].哈尔滨:哈尔滨工程大学,2016(Shen Xinhui.Investigation on dynamic fracture toughness experimental technique under stress wave load.[Ph D Thesis].Harbin:Harbin Engineering University,2016(in Chinese))
22 Richard HA.A new compact shear specimen.International Journal of Fracture,1981,17(5):105-107
23 Anderson TL.Fracture Mechanics,Foundations and Applications.Boca Raton,CRC Press,1991
24王自强,陈少华.高等断裂力学.北京:科学出版社,2009:43-76(Wang Ziqiang,Chen Shaohua.Advanced Fracture Mechanics.Beijing:Science Press,2009:43-76(in Chinese))
25 Xu Z,Li Y.A novel method in determination of dynamic fracture toughness under mixed mode I/II impact loading.International Journal of Solids and Structures,2012,49:366-376
26郦正能.应用断裂力学.北京:北京航空航天大学出版社,2012:64-72(Li Zhengneng.Applied Fracture Mechanics.Beijing:Beihang University Press,2012:64-72(in Chinese))
27 Peters WH,Ranson WH.Digital imaging technique in experimental mechanics.Opt Eng,1982,21(3):427-431
28 Yamaguchi I.Speckle displacement and deformation in the diffraction and image fields for small object deformation.Opt Acta,1981,28(10):1359-1376
29周忠彬,陈鹏万,黄风雷.PBX材料宏细观断裂行为的数字散斑相关法实验研究.高压物理学报,2011,25(1):1-7(Zhou Zhongbin,Chen Pengwan,Huang Fenglei.An experimental study on the micro/macro fracture behavior of PBX using digital speckle correlation method.Chinese Journal of High Pressure Physics,2011,25(1):1-7(in Chinese))
30邹广平,汪艳伟,唱忠良等.基于数字散斑相关法的紧凑拉伸试样断裂韧性实验研究.实验力学,2015,30(3):275-281(Zou Guangping,Wang Yanwei,Chang Zhongliang,et al.Experimental study of compact tension specimen fracture toughness based on digital speckle correlation method.Journal of Experimental Mechanics,2015,30(3):275-281(in Chinese))