Modeling the effect of the striker geometry on the wave propagation pattern in the Split-Hopkinson pressure bar test using the discrete element method

Document Type : Research Paper

Authors

Faculty of Mining, Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran

Abstract

Split Hopkinson Pressure Bars (SHPB) test is widely used among the various methods for investigating the dynamic behavior of rocks at high strain rates. Various factors affect the waveform and the results of this test. In this study, the aim was to investigate the effect of geometrical parameters of strikers including the effect of shape, length, and impact cross-section width (ICSW) on the waveform induced in the SHPB test using numerical modeling. For this purpose, in the first stage, the required information including geometrical properties and the required micro-parameters have been collected from two laboratory and numerical modeling studies. Then, the initial model was constructed using the discrete element numerical method (DEM), and its results were compared with laboratory and numerical results. Evaluation of the effect of striker shape demonstrated that SS strikers have induced a semi-sinusoidal wave and CS strikers have induced a quasi-rectangular wave. Among the waveform properties, the wavelength was strongly related to the geometric properties of the strikers in both CS and SS types in a way that was directly related to the striker’s length and inversely related to the ICSW. On the other hand, the maximum amplitude is directly related to the striker’s length and ICSW in both CS and SS types. According to the results, the use of SS strikers is more appropriate according to the waveform, and its geometric properties can be determined according to the problem requirement, using numerical modeling results.

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[1] Aziznejad S, Esmaieli K, Hadjigeorgiou J, Labrie, D (2018) Response of jointed rock masses subjected to impact loading. J Rock Mech and Geotech Eng 10(4), 624-634, https://doi.org/
10.1016/j.jrmge.2017.12.006.
[2] Majzoobi G.H, Rahmani K, Lahmi S (2019) Determination of length to diameter ratio of the bars in torsional Split Hopkinson bar. Measurement 143, 144 154, https://doi.org/10.1016/
j.measurement.2019.04.054.
[3] Gerlach R, Kettenbeil C, Petrinic N (2012)A new split Hopkinson tensile bar design. Int J Impact Eng 50, 63-67, https://doi.org
/10.1016/j.ijimpeng.2012.08.004.
[4] Li, X, Yang Z, Zhou Z (2014) Numerical Simulation of the Rock SHPB Test with a Special Shape Striker Based on the Discrete Element Method. Rock Mech Rock Eng 47:1693–1709, https://doi.org/10.1007/s00603-013-0484-6.
[5] Lok T.S, Li X.B, Liu D.S, Zhao P.J (2002) Testing and response of large diameter brittle materials subjected to high strain rate. J Material Civil Eng 14(3):262–269, https://doi.org/10.1061/
(ASCE)0899-1561(2002)14:3(262).
[6] Li X.B, Lok T.S, Zhao J, Zhao P.J (2000) Oscillation elimination in the Hopkinson bar apparatus and resultant complete dynamic stress–strain curves for rocks. Int J Rock Mech Min Sci 37(7):1055–1060, https://doi.org/10.1016/S1365-1609(00)00037-X.
[7] Kolsky H (1949) An investigation of the mechanical properties of materials at very high rates of loading. Proc Phys Soc Lond SerB 62(11), 676–700, https://doi.org/10.1088/0370-1301/62/11/302.
[8] Zhou Z.l, Li X, Liu A, Zou Y (2017) Dynamic behavior of rock during its post failure stage in SHPB tests. Transactions of Nonferrous Metals Society of China 27(1), 184-196, https://doi.org/10.1016/S1003-6326(17)60021-9.
[9] Peng K, Gao K, Liu J, Liu Y, Zhang Zh, Fan X, Yin X, Zhng Y, Huang G (2017) Experimental and Numerical Evaluation of Rock Dynamic Test with Split-Hopkinson Pressure Bar. Advances in Materials Science and Engineering, Article ID 2048591, https://doi.org/10.1155/2017/2048591.
[10] Zhang Q.B, ZhaoJ (2014) A Review of Dynamic Experimental Techniques and Mechanical Behaviour of Rock Materials. Rock Mech Rock Eng 47:1411–1478, https://doi.org/ 10.1007/s00603-013-0463-y.
[11] Xu Y, Dai F, Xu N.W, Zhao T (2016) Numerical Investigation of Dynamic Rock Fracture Toughness Determination Using a Semi-Circular Bend Specimen in Split Hopkinson Pressure Bar Testing. Rock Mech Rock Eng 49:731–745, https://doi.org/
10.1007/s00603-015-0787-x.
[12] Chen X, Ge L, Zhou J, Wu S (2015) Experimental Study on Split Hopkinson Pressure Bar Pulse-Shaping Techniques for Concrete. J Material and Civil En 28(5): 04015196, 1-9. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001494.
[13] Baranowski P, Malachowski J, Gieleta R, Damaziak K, Mazurhiewicz L, Kolodziejcyk D (2013) Numerical study for determination of pulse shaping design variables in SHPB apparatus. Technical science 61)2(, 459-466, https://doi.org/
10.2478/bpasts-2013-0045.
[14] Panowicz R, Janiszewski J, Kochanowski K (2019) Effects of Sample Geometry Imperfections on the Results of Split Hopkinson Pressure Bar Experiments. Experimental Techniques 43:397–403, https://doi.org/10.1007/s40799-018-0293-7.
 [15] Liao Z.Y, Zhu J.B, Xia K.W, Tang C.A (2017) Determination of Dynamic Compressive and Tensile Behavior of Rocks from Numerical Tests of Split Hopkinson Pressure and Tension Bar.  Rock Mech Rock Eng 49(10), 3917-3934, https://doi.org/10.1007/
s00603-016-0954-8.
[16] Zhou ZL, Li X.B, Liu A.H, Zou Y (2011) Stress uniformity of split Hopkinson pressure bar under half-sine wave loads. Int J Rock Mech Min Sci 48(4):697–701, https://doi.org/10.1016/
j.ijrmms.2010.09.006.
[17] Itasca Consulting Group Inc (2016) PFC2d user’s manual, version 5.0. Minneapolis
[18] Nikkhah M (2017) Numerical assessment of influence of confining stress on Kaiser effect using distinct element method. Journal of mining and environment 8(2): 215-226 https://doi.org/10.22044/jme.2016.674