Shock Wave Overpressure Measurement: Comparison Between Two Piezoelectric Sensor Materials

2011 ◽

Vol 314-316 ◽

pp. 639-642

Author(s):

Jun Feng Cai ◽

Jian Zheng Yi ◽

Tian Peng Li

Keyword(s):

Shock Wave ◽

Wave Attenuation ◽

Piezoelectric Sensor ◽

Shock Wave Attenuation ◽

Wave Measurement ◽

Test Circuit ◽

Explosion Load

In the paper, The PVDF piezoelectric sensor was customized and the structure and test circuit of PVDF piezoelectric sensor is introduced. The polyurethane(PUF) reinforced by ultra high molecular weigh polyethylene (UHMWPE) material(UHMWPE-PUF composites) was synthesized. The pressure in UHMWPE-PUF composites under explosion load was measured and shock wave attenuation waveform is gained and the data is analyzed. The studies showed that PVDF piezoelectric firm sensor is suitable to shock wave measurement in material and UHMWPE- PUF composites can improve maximally shock wave attenuation properties of the material and have good applied outlook in the realm of anti-explosion.

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Pressure Load Characteristics of Nonideal Explosives in a Simulation Cabin

Shock and Vibration ◽

10.1155/2019/6862134 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Chuan-hao Wang ◽

Shu-shan Wang ◽

Jing-xiao Zhang

Keyword(s):

Shock Wave ◽

Low Frequency ◽

Piezoelectric Sensor ◽

Calculation Model ◽

Incident Shock ◽

Incident Shock Wave ◽

Wave Load ◽

Piezoresistive Sensor ◽

Load Characteristics ◽

The Ideal

In this study, an aluminum-containing charge was exploded in an enclosed simulation cabin to explore the characteristics of two types of damaging pressure loads formed by internal explosions: the first incident shock wave and the quasistatic pressure. A high-frequency piezoelectric sensor was used to measure the first incident shock wave and a low-frequency piezoresistive sensor was used to measure the quasistatic pressure. After obtaining effective experimental data, the experimental results were compared with the values obtained by the classical calculation model. The results show that the pressure loads generated by the internal explosions from the ideal explosive and the aluminum-containing explosive share similar load characteristics, given the same mass and benchmark explosive. The difference between the two explosives primarily lies in the amplitude of the load parameters. The aluminum-containing explosive has lower first incident shock wave and higher quasistatic pressure than that of the ideal explosive. For the peak overpressure of the first incident shock wave, the explosion shock wave load parameters of the aluminum-containing explosive, which are calculated based on the explosion heat theory, are higher than the measured values. The peak quasistatic overpressure is directly related to the total energy released by the explosion; however, they are hardly correlated with the reaction process. Therefore, the aerobic postcombustion reaction of the aluminum-containing explosive does not affect the analysis and calculation of the peak quasistatic overpressure. As a result, given the heat value of the explosive, the peak quasistatic overpressure of the explosive can accurately be obtained.

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A new type of defect structure in 124-superconducting oxide revealed by HREM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089779 ◽

1991 ◽

Vol 49 ◽

pp. 1092-1093

Author(s):

R. Sharma ◽

B.L. Ramakrishna ◽

N.N. Thadhani ◽

D. Hianes ◽

Z. Iqbal

Keyword(s):

Shock Wave ◽

Defect Structure ◽

Neutron Radiation ◽

Weak Links ◽

Defect Structures ◽

New Materials ◽

New Type ◽

Current Densities ◽

Processing Techniques ◽

Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

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Investigation of shock-wave deformation history from recovered structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143754 ◽

1986 ◽

Vol 44 ◽

pp. 434-435

Author(s):

M.A. Mogilevsky ◽

L.S. Bushnev

Keyword(s):

Shock Wave ◽

Plastic Deformation ◽

Dislocation Density ◽

Shock Waves ◽

Shock Front ◽

Single Crystals ◽

Residual Deformation ◽

Deformation Structure ◽

Deformation History ◽

Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

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Electron microscopy study of shock synthesis of silicides

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151647 ◽

1993 ◽

Vol 51 ◽

pp. 1162-1163

Author(s):

Kenneth S. Vecchio

Keyword(s):

Shock Wave ◽

Plastic Deformation ◽

Close Contact ◽

Microscopy Study ◽

High Energy ◽

Electron Microscopy Study ◽

Powder Materials ◽

Porous Powder ◽

Wave Effects ◽

Wave Passage

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.

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