New Impact Testing Methods for Sheet Metals Based on SHPB Technique

2007 ◽  
Vol 566 ◽  
pp. 255-260
Author(s):  
Tadashi Hasebe ◽  
Yutaka Imaida

This paper proposes new impact testing methods applicable to sheet metals both under tension and compression based on widely used split Hopkinson pressure bar (SHPB) technique. Explicit dynamic finite element simulations by using LS-DYNA 3D are systematically conducted for several specimen clamping conditions to seek the appropriate methodologies to realize the two tests. For the tensile test, a method which can reduce stress oscillations that usually appear in the measured stress-strain curves is proposed and is devised to be used with SHPB technique. For the compression test, a candidate which can restrict buckling of the specimen is proposed. The method uses a special die-set sandwiching the sheet metal specimen which is simultaneously compressed without disturbing the planar stress wave to be propagated.

2017 ◽  
Vol 19 (10) ◽  
pp. 1700076 ◽  
Author(s):  
Tomáš Fíla ◽  
Petr Zlámal ◽  
Ondřej Jiroušek ◽  
Jan Falta ◽  
Petr Koudelka ◽  
...  

2021 ◽  
Vol 11 (21) ◽  
pp. 9882
Author(s):  
Jiangping Chen ◽  
Weijun Tao ◽  
Shumeng Pang

In this study, a total of 30 3D re-entrant honeycomb specimens made of polyamide were fabricated with various configurations by using the additive manufacturing (AM) technique. Split Hopkinson Pressure Bar (SHPB) tests were conducted on the RH specimens at different impact velocities. The incident, reflected and transmitted waveforms can well explain the wave propagation and energy absorption characteristics of the specimens, which can help us to understand and analyse the process of impact loading. The stress–strain curves, energy absorption ability and failure modes of SHPB tests with different impact velocities and quasi-static compression tests were analysed and compared, and it was found that the flow stress and energy absorption ability of the specimens subjected to impact load were much improved. Among the tested specimens, specimen C2, with a smaller re-entrant angle θ, displayed the best energy absorption ability, which was 1.701 J/cm3 at the impact velocity of 22 m/s and was 5.1 times that in the quasi-static test. Specimen C5 had the longest horizontal length of the diagonal bar L0, and its energy absorption was 1.222 J/cm3 at the impact velocity of 22 m/s and was 15.7 times that in the quasi-static test, reflecting the superiority of a structurally stable specimen in energy absorption under impact loading. The test results can provide a reference for the optimization of the design of the same or similar structures.


2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient


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