Analysis on the waveform features of the split Hopkinson pressure bar tests of plain concrete specimen

Dispersion of an elastic wave propagating in a 76.2-mm-diameter (3 in.) Split Hopkinson Pressure Bar system was investigated with two consecutive pulses recorded in the transmitter bar. Assuming that the dispersive high frequency oscillatory components riding on the top of the main pulse originate from the first mode vibration, the dispersion was corrected by using the Fast Fourier Transform (FFT) and Fourier series expansion numerical schemes. The good agreement validates the assumption that only the first mode was significant. The dispersion correction technique was employed in a test of a concrete specimen having the same diameter as that of the SHPB. Better agreement of the two specimen-bar interface stresses versus time and fewer oscillations in the stress-strain curve demonstrated advantages of the application of dispersion corrections.

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Study on Toughening Effect in EPS Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.105-107.1717 ◽

2011 ◽

Vol 105-107 ◽

pp. 1717-1722

Author(s):

De Hui Zhao ◽

Jin Yu Xu ◽

Er Lei Bai

Keyword(s):

Strain Rate ◽

Volume Fraction ◽

Split Hopkinson Pressure Bar ◽

Plain Concrete ◽

Rate Dependency ◽

Hopkinson Pressure Bar ◽

Effect Mechanism ◽

Average Strain Rate ◽

Split Hopkinson ◽

Pressure Bar

To study on the toughing effect of EPS in the plain concrete, the EPS concrete with 10%,20%,30%,40%,50% EPS volume fraction were prepared. Taking specific energy absorption as the index, the toughing effect of EPS concrete with different EPS volume fraction under impact loading were studied using a 100-mm-diameter split Hopkinson pressure bar(SHPB) apparatus, and the toughing effect mechanism of the concrete was discussed. The results show that the toughing effect of the EPS concrete increases with the average strain rate for the strain rate effect, which takes on obvious strain rate dependency. For the EPS microscopic structure effect, the toughing effect of the EPS concrete increases with the EPS volume fraction in 10~30%. Its toughing effect reduces somewhat when the EPS volume fraction reaches 40~50%. To improve the deformation property, the optimum volume fraction of EPS is 20%.

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Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

Metrology and Measurement Systems ◽

10.2478/mms-2013-0047 ◽

2013 ◽

Vol 20 (4) ◽

pp. 555-564 ◽

Cited By ~ 12

Author(s):

Wojciech Moćko

Keyword(s):

Test Bench ◽

Split Hopkinson Pressure Bar ◽

Dynamic Deformation ◽

Spectral Width ◽

Hopkinson Pressure Bar ◽

Computing Environment ◽

Split Hopkinson ◽

Pressure Bar ◽

The Impact ◽

Bench Model

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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