scholarly journals NUMERICAL MODELLING OF WAVE SHAPES DURING SHPB MEASUREMENT

2019 ◽  
Vol 25 ◽  
pp. 25-31
Author(s):  
Radim Dvořák ◽  
Petr Koudelka ◽  
Tomáš Fíla
Keyword(s):  
Parametric Analysis ◽  
Pulse Shaping ◽  
Split Hopkinson Pressure Bar ◽  
Sensitivity Study ◽  
Hopkinson Pressure Bar ◽  
Pulse Shaper ◽  
Geometric Properties ◽  
Element Size ◽  
Split Hopkinson ◽  
Pressure Bar

The paper aims at the numerical simulation of the wave propagation in compressive Split Hopkinson Pressure Bar (SHPB) experiment. The paper deals with principles of SHPB measurement, optimisation of a numerical model and techniques of pulse shaping. The parametric model of the typical SHPB configuration developed for LS-DYNA environment is introduced and optimised (in terms of element size and distribution) using the sensitivity study. Then, a parametric analysis of a geometric properties of the pulse shaper is carried out to reveal their influence on a shape of the incident pulse. The analysis is algorithmized including the pre- and post-processing routines to enable automated processing of numerical results and comparison with the experimental data. Results of the parametric analysis and the influence of geometric properties of the pulse shaper (diameter, length) on the incident wave are demonstrated.

Dynamic Compressive Behavior of Granite under Active Confinement

2011 ◽  
Vol 291-294 ◽  
pp. 1227-1232 ◽  
Author(s):  
Gang Chen ◽  
Yu Chun Kuang ◽  
Xi Cheng Huang ◽  
Ai Min Xu
Keyword(s):  
Strain Rate ◽  
Pulse Shaping ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Pulse Shaper ◽  
Safety Requirements ◽  
Split Hopkinson ◽  
Active Confinement ◽  
Pressure Bar ◽  
Stress Uniformity

The behaviour of geologic material such as granite under impact loading is involved in the study of safety requirements of structures in extreme simulations such as earthquakes, accidental impacts or explosions. Based on incident pulse shaping design of quasi-brittle material for dynamic tests, experiments on granite under uniaxial and active confinement conditions are conducted with the split Hopkinson pressure bar(SHPB). By adding the soft material mass as the pulse shaper, the stress uniformity in the specimens before fracture is ensured and the fluctuation of test data due to incident stress pulse is avoid. The experimental results show that the compressive strength is increasing with the strain rate and the confined pressure. The fragments size decreases with the strain rate. The research method and conclusion could be used to analyze the dynamic behavior of the other brittle materials.

scholarly journals Influence of Imperfect Position of a Striker and Input Bar on Wave Propagation in a Split Hopkinson Pressure Bar (SHPB) Setup with a Pulse-Shape Technique

2020 ◽  
Vol 10 (7) ◽  
pp. 2423 ◽  
Author(s):  
Robert Panowicz ◽  
Marcin Konarzewski
Keyword(s):  
Wave Propagation ◽  
Inclination Angle ◽  
High Frequency ◽  
Pulse Shape ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Pulse Shaper ◽  
Split Hopkinson ◽  
Pressure Bar

The effect of using a pulse shaper technique, such as rounding a striker or applying a pulse shaper on the signals recorded with the split Hopkinson pressure bar (SHPB) technique, when the striker and the input bar are in an imperfect position, was investigated. Two of the most common cases have been analyzed: an offset of the symmetry axes of the striker and the input bar; and an inclination angle between the striker and the input bar. LS-Dyna software was used to examine this problem numerically. The inclination angle imperfection has a significant impact on signal disturbances, whereas the use of a rounded striker significantly affects the limitation of the vibration flexural modes. In all considered cases, a slight imperfection causes a reduction in the high-frequency Pochhammer–Chree oscillations.

scholarly journals Numerical study for determination of pulse shaping design variables in SHPB apparatus

2013 ◽  
Vol 61 (2) ◽  
pp. 459-466 ◽  
Author(s):  
P. Baranowski ◽  
J. Malachowski ◽  
R. Gieleta ◽  
K. Damaziak ◽  
L. Mazurkiewicz ◽  
...  
Keyword(s):  
Pulse Shaping ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Study ◽  
Experimental Tests ◽  
Peak Shape ◽  
Hopkinson Pressure Bar ◽  
Design Variables ◽  
Split Hopkinson ◽  
Pulse Peak ◽  
Pressure Bar

Abstract High strain rate experimental tests are essential in a development process of materials under strongly dynamic conditions. For such a dynamic loading the Split Hopkinson Pressure Bar (SHPB) has been widely used to investigate dynamic behaviour of various materials. It was found that for different materials various shapes of a generated wave are desired. This paper presents a parametric study of Split Hopkinson Pressure Bar in order to find striker’s design variables, which influence the pulse peak shape in the incident bar. With experimental data given it was possible to verify the developed numerical model, which was used for presented investigations. Dynamic numerical simulations were performed using explicit LS-Dyna code with a quasi-optimization process carried out using LS-Opt software in order to find striker’s design variables, which influence the pulse peak shape.

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