直接撞击式大变形霍普金森压杆实验技术
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摘要
作为高应变率材料力学性能测试的主要手段,霍普金森压杆实验的测试时长受到压杆长度限制,试件无法在较宽广的应变率下实现大变形.由此提出了一种在有限杆长下实现大变形加载的实验技术,该技术将传统上用于超高应变率实验的直接撞击方法应用于较低应变率下的材料动态性能测试,可实现102s-1量级应变率下材料较大变形下的动态应力—应变曲线测试.实际应用表明该方法简单有效.并且文中也对该技术的适用范围、实验装置的几何参数及材料参数对测试结果的影响进行了分析讨论.
As a major method of mechanical property test under high strain rate, the time duration of the Hopkinson Bar test is limited by the length of the pressure bars, and the specimen can't achieve large deformation in a wide range of strain rate. In this paper, an experimental technique for large deformation loading with finite bar length is presented. The traditional method of direct impact test for ultra-high strain rate test has been applied to the dynamic performance testing of materials in relatively lower strain rate. Using this technique, the dynamic stress-strain curve of materials under the strain rate in the order of 102 s-1 can be obtained. Practical application shows that the method is simple and effective. The range of application of the technique, the geometrical parameters of the experimental device and the influence of the material parameters on the test results are also discussed.
As a major method of mechanical property test under high strain rate, the time duration of the Hopkinson Bar test is limited by the length of the pressure bars, and the specimen can't achieve large deformation in a wide range of strain rate. In this paper, an experimental technique for large deformation loading with finite bar length is presented. The traditional method of direct impact test for ultra-high strain rate test has been applied to the dynamic performance testing of materials in relatively lower strain rate. Using this technique, the dynamic stress-strain curve of materials under the strain rate in the order of 102 s-1 can be obtained. Practical application shows that the method is simple and effective. The range of application of the technique, the geometrical parameters of the experimental device and the influence of the material parameters on the test results are also discussed.
引文
[1]Gray III G T.Classic Split-Hopkinson Pressure Bar Testing[M]//Kuhn H,Medlin D.SAM Handbook,Mechanical Testing and Evaluation,Vol.8,Materials Park,OH:ASM International,2000:462-476.
[2]Chen W W,Song B.Split Hopkinson(Kolsky)Bar:Design Testing and Applications[M].New York:Springer Press,2015.
[3]韩李斌,杨黎明.泡沫混凝土动态力学性能及破坏形式[J].宁波大学学报(理工版),2017,30(1):68-72.
[4]Zhao H,Gary G.A new method for the separation of waves:Application to the SHPB technique for an unlimited duration of measurement[J].Journal of the Mechanics&Physics of Solids,1997,45(7):1185-1202.
[5]Dharan C K H,Hauser F E.Determination of stress-strain characteristics at very high strain rates[J].Experimental Mechanics,1970,10(9):370-376.
[6]Gorham D A,Pope P H,Field J E.An improved method for compressive stress-strain measurements at very high strain rates[J].Proceedings:Mathematical and Physical Sciences,1992,438(1902):153-170.
[7]Park S W,Zhou M.Separation of elastic waves in split Hopkinson bars using one-point strain measurements[J].Experimental Mechanics,1999,39(4):287-294.
[8]宋力,胡时胜.SHPB测试中的均匀性问题及恒应变率[J].爆炸与冲击,2005,25(3):207-216.
[2]Chen W W,Song B.Split Hopkinson(Kolsky)Bar:Design Testing and Applications[M].New York:Springer Press,2015.
[3]韩李斌,杨黎明.泡沫混凝土动态力学性能及破坏形式[J].宁波大学学报(理工版),2017,30(1):68-72.
[4]Zhao H,Gary G.A new method for the separation of waves:Application to the SHPB technique for an unlimited duration of measurement[J].Journal of the Mechanics&Physics of Solids,1997,45(7):1185-1202.
[5]Dharan C K H,Hauser F E.Determination of stress-strain characteristics at very high strain rates[J].Experimental Mechanics,1970,10(9):370-376.
[6]Gorham D A,Pope P H,Field J E.An improved method for compressive stress-strain measurements at very high strain rates[J].Proceedings:Mathematical and Physical Sciences,1992,438(1902):153-170.
[7]Park S W,Zhou M.Separation of elastic waves in split Hopkinson bars using one-point strain measurements[J].Experimental Mechanics,1999,39(4):287-294.
[8]宋力,胡时胜.SHPB测试中的均匀性问题及恒应变率[J].爆炸与冲击,2005,25(3):207-216.