A dynamic tensile method for M-shaped specimen loaded by Hopkinson pressure bar
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摘要: 采用传统分离式Hopkinson压杆进行M型试样的动态拉伸实验，可避免试样与杆的连接问题，但该方法并未得到发展和验证。本文中，采用有限元数值分析和实验方法，对M型试样动态拉伸实验进行分析和改进。结果表明：（1）改进的封闭M型试样，可以增强试样整体刚度，有效减少试样畸变引起的附加弯矩对拉伸标段的影响，方便通过Hopkinson压杆加载实现一维拉伸变形；（2）采用试样刚度系数修正法，可消除M型试样整体结构的弹性变形对测试的影响，精确获得试样拉伸标段的塑性应变；（3）高加载率下，建议采用波形整器加载，可显著减少试样结构引起的载荷震荡现象、改善两端的应力平衡，获得准确的动态拉伸应力应变曲线，实现5 900 s−1甚至更高应变率下的动态拉伸实验。研究方法可为M型试样拉伸实验设计和应用提供参考。
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关键词:
- M型试样 /
- 动态拉伸 /
- Hopkinson压杆 /
- 高应变率 /
- 应力应变曲线
Abstract: The M-shaped specimen can be used in dynamic tensile testing only by using the conventional split Hopkinson pressure bar, which do not need the connection between specimen and bars. But the feasibility of this method has not been further verified widely. In this paper, the dynamic tensile testing of M-shaped specimen were analyzed and improved by the finite element and experimental method. The results show that: (1) the improved closed M-shaped specimen was proposed, which can enhance the total stiffness of the specimen, effectively reduce the distortion deformation of the specimen and the influence of additional bending moment in the tensile gage section, and easily realize dynamic tensile through Hopkinson pressure bar; (2) the influence of the elastic deformation of the M-specimen on the tensile displacement could be corrected by the stiffness coefficient of specimen, the plastic strain of the tensile section of the specimen can be analyzed accurately; (3) under higher loading rate, it is suggested to adopt loading through the pulse shaper of Hopkinson bar, which can significantly improve the wave oscillation and stress balance at both ends of the specimen, obtain an accurate dynamic stress-strain curve, and realize the dynamic tensile test up to 5 900 s−1 or even higher strain rate. The study provides an important reference for the design and application of tensile test of M-shaped specimen. -
图 1 M型试样的拉伸加载原理
Figure 1. Schematic of quasi-static and dynamic tensile test for M-specimen
图 3 M型试样的加载力、压缩位移和整体变形
Figure 3. Dynamic force, compression displacement and global deformation of M-specimen
图 4 拉伸标段不同位置点的应力比较和轴向应力演化
Figure 4. Stress comparison and axial stress evolution at different points of tensile section
图 7 三角波加载下的入射波、反射波和透射波
Figure 7. Incident, reflected and transmitted wave by pulse shaper
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[1] DAVIES R M. A critical study of the Hopkinson pressure bar [J]. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1948, 240(821): 375–457. DOI: 10.1098/rsta.1948.0001. [2] KOLSKY H. An investigation of the mechanical properties of materials at very high rates of loading [J]. Proceedings of the Physical Society, Section B, 1949, 62(11): 676–700. DOI: 10.1088/0370-1301/62/11/302. [3] GRAY Ⅲ G T, BLUMENTHAL W R. Split-Hopkinson pressure bar testing of soft materials [C] // KUHN H, MEDLIN D. SAM handbook: mechanical testing and evaluation. Materials Park, OH: ASM International, 2000: 488−496. [4] 王礼立. 应力波基础[M]. 2版. 北京: 国防工业出版社, 2005. [5] 胡时胜, 王礼立, 宋力, 等. Hopkinson压杆技术在中国的发展回顾 [J]. 爆炸与冲击, 2014, 34(6): 641–657. DOI: 10.11883/1001-1455(2014)06-0641-17.HU S S, WANG L L, SONG L, et al. Review of the development of Hopkinson pressure bar technique in China [J]. Explosion and Shock Waves, 2014, 34(6): 641–657. DOI: 10.11883/1001-1455(2014)06-0641-17. [6] DUFFY J, CAMPBELL J D, HAWLEY R H. On the use of a torsional split Hopkinson bar to study rate effects in 1100-0 aluminum [J]. Journal of Applied Mechanics, 1971, 38(1): 83–91. DOI: 10.1115/1.3408771. [7] NICHOLAS T. Tensile testing of materials at high rates of strain [J]. Experimental Mechanics, 1981, 21(5): 177–185. DOI: 10.1007/BF02326644. [8] OGAWA K. Impact-tension compression test by using a split-Hopkinson bar [J]. Experimental Mechanics, 1984, 24(2): 81–86. DOI: 10.1007/BF02324987. [9] STAAB G H, GILAT A. A direct-tension split Hopkinson bar for high strain-rate testing [J]. Experimental Mechanics, 1991, 31(3): 232–235. DOI: 10.1007/BF02326065. [10] 宋顺成, 田时雨. Hopkinson冲击拉杆的改进及应用 [J]. 爆炸与冲击, 1992, 12(1): 62–67.SONG S C, TIAN S Y. Dynamic tensile testing of materials using the hollow Hopkinson bars instead of the solid Hopkinson bars [J]. Explosion and Shock Waves, 1992, 12(1): 62–67. [11] 胡时胜, 邓德涛, 任小彬. 材料冲击拉伸实验的若干问题探讨 [J]. 实验力学, 1998, 13(1): 9–14.HU S S, DENG D T, REN X B. A study on impact tensile test of materials [J]. Journal of Experimental Mechanics, 1998, 13(1): 9–14. [12] 田宏伟, 郭伟国. 动态拉伸试验中试样应变测试的有效性分析 [J]. 实验力学, 2008, 23(5): 403–410.TIAN H W, GUO W G. Validity analysis of sample strain measurement in dynamic tensile experiment [J]. Journal of Experimental Mechanics, 2008, 23(5): 403–410. [13] 彭刚, 冯家臣, 胡时胜, 等. 纤维增强复合材料高应变率拉伸实验技术研究 [J]. 实验力学, 2004, 19(2): 136–143. DOI: 10.3969/j.issn.1001-4888.2004.02.002.PENG G, FENG J C, HU S S, et al. A Study on high strain rate tensile experimental technique aimed at fiber reinforced composite [J]. Journal of Experimental Mechanics, 2004, 19(2): 136–143. DOI: 10.3969/j.issn.1001-4888.2004.02.002. [14] MOHR D, GARY G. M-shaped specimen for the high-strain rate tensile testing using a split Hopkinson pressure bar apparatus [J]. Experimental Mechanics, 2007, 47(5): 681–692. DOI: 10.1007/s11340-007-9035-y. [15] CADONI E, FORNI D, GIELETA R, et al. Tensile and compressive behaviour of S355 mild steel in a wide range of strain rates [J]. The European Physical Journal Special Topics, 2018, 227(1−2): 29–43. DOI: 10.1140/epjst/e2018-00113-4. [16] 史同亚, 刘东升, 陈伟, 等. 激光选区熔化增材制造GP1不锈钢动态拉伸力学响应与层裂破坏 [J]. 爆炸与冲击, 2019, 39(7): 49–60. DOI: 10.11883/bzycj-2019-0015.SHI T Y, LIU D S, CHENG W, et al. Dynamic tensile behavior and spall fracture of GP1 stainless steel processed by selective laser melting [J]. Explosion and Shock Waves, 2019, 39(7): 49–60. DOI: 10.11883/bzycj-2019-0015. [17] SONG B, NISHIDA E, SANBORN B, et al. Compressive and tensile stress-strain responses of additively manufactured (AM) 304 L stainless steel at high strain rates [J]. Journal of Dynamic Behavior of Materials, 2017, 3(3): 412–425. DOI: 10.1007/s40870-017-0122-6. [18] 丁利, 李怀学, 王玉岱, 等. 热处理对激光选区熔化成形316不锈钢组织与拉伸性能的影响 [J]. 中国激光, 2015, 42(4): 0406003. DOI: 10.3788/CJL201542.0406003.DING L, LI H X, WANG Y D, et al. Heat treatment on microstructure and tensile strength of 316 stainless steel by selective laser melting [J]. Chinese Journal of Lasers, 2015, 42(4): 0406003. DOI: 10.3788/CJL201542.0406003. -
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