scholarly journals KONCEPCJA BADAŃ EKSPERYMENTALNYCH ZACHOWANIA SIĘ MATERIAŁU OBSYPKI PIASKOWEJ UKRYĆ OCHRONNYCH DLA LUDNOŚCI CYWILNEJ

Author(s):  
Kamil Sobczyk ◽  
Ryszard Chmielewski ◽  
Leopold Kruszka

The article proposes the concept of experimental dynamic tests of aggregate behavior - sand used as a material for covering temporary protective shelters for the population and civil defense. These shelters are part of the construction shielding infrastructure useful in crisis situations. Laboratory tests of loose soil, including sand, with impact loads, are based on the Split Hopkinson Pressure Bar using a clamp. The work describes both this experimental method and the original laboratory stand for impact tests based on a pneumatic launcher with a projectile - bar. This position was built at the Institute of Civil Engineering of the Military University of Technology taking into account the requirements of generally applicable legal provisions. Examples of preliminary experimental research on the behavior of selected aggregate - dry sand under dynamic load - are presented.

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


2015 ◽  
Vol 816 ◽  
pp. 795-803
Author(s):  
Yan Ling Wang ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Rui Liu

The mechanical properties and fracture failure behavior of the near β-type Ti-5Al-5Mo-5V-3Cr-X (X = 1Fe or 1Zr) titanium alloys were studied by Split Hopkinson Pressure Bar (SHPB) experiment under the dynamic loading conditions at a strain rate of 1.5 × 103 s-1–5.0 × 103 s-1. Results showed that the SHPB specimen fractured in the direction of maximum shearing stress at an angle of 45° with the compression axis. The fracture surface revealed the shear and tension zones with cleavage steps and parabolic dimples. Severe early unloading was observed on the Ti-5553 alloy under a strain rate of 4,900 s-1 loading condition, and the dynamic property of the Ti-55531Zr alloy was proved to be the optimal.


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