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Depolarization and Electrical Response of Porous PZT 95/5 Ferroelectric Ceramics under Shock Wave compression

Chinese Physics Letters 2014年第7期31卷 179-183页

作者：王智珠蒋一萱张攀王省哲贺红亮 Key Laboratory of Mechanics on Disaster and Environment in Western China (Ministry of Education) College of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics China Academy of Engineering Physics Mianyang 621900

The release of bound charges by shock wave loading of poled lead zirconate titanate （PZT 95/5） ferroelectric ceramics can result in a high-power electrical energy output. In this study, a theoretical formulation describing the depolarization and electrical response of porous PZT 95/5 ceramics in the normal mode to shock wave compression loading perpendicular to the polarization direction is developed. The depoling process in porous poled PZT 95/5 ceramics is analyzed by using a parallel circuit consisting of a current source, capacitance, conductance and a circuit load. This modeling takes the effects of porosity on wave velocity and remanent polarization and dielectric constant into account, and the effects of variations in dielectric constant and conductivity in the shocked region are assessed. The output current characteristics of porous PZT 95/5 ceramics under short-circuit and resistive load conditions are analyzed and compared with the experiment, with the results showing that theoretical predictions taking into consideration the porosity of ferroelectric ceramics are in close agreement with the experimentally measured electrical response of porous PZT 95/5 under shock wave compression loading.

关键词： FERROELECTRIC ceramics SHOCK waves POROUS materials compression loads PERMITTIVITY

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Critical-Current Degeneration Dependence on Axial Strain of Bi-based Superconducting Multi-filamentary Composite Tapes

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Chinese Physics Letters 2014年第4期31卷 155-158页

作者： GAO Pei-Feng WANG Xing-Zhe Key Laboratory of Mechanics on Western Disaster and Environment (Ministry of Education) and College of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000

Superconducting materials are always severely restricted in practical engineering applications due to their carrying- current degradation under mechanical loads. Based on Ekin＇s exponential model and Weibull＇s distribution func- tion, we propose an empirical degradation model for describing the mechanical deformation influence on the critical-current of Bi-based superconducting multi-filamentary composite tapes under axial loading. The critical currents of superconducting tapes depending on the axial strain are investigated analytically. It is shown that the predictions by the developed degradation model agree with the experimental data, in the processes of axial mechanical loading and unloading on the samples. The effect of the critical tension and compression damage strains on the normalized critical currents is also discussed.

关键词： CRITICAL currents MULTIFILAMENTARY superconductors WEIBULL distribution SUPERCONDUCTING tape compression loads

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Behaviour of Reinforced Concrete Columns Strengthened with Ferrocement under compression Conditions: Experimental Approach

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World Journal of Engineering and Technology 2016年第4期4卷 608-622页

作者： Adnan Al-Sibahy Civil Engineering Department University of Al-Qadisiyah Al Diwaniyah Iraq

This paper reports a study based upon experimental investigation which aims to assess the behaviour of reinforced concrete columns strengthened with a new configuration of steel wire mesh as part of ferrocement layer under the action of axial compression loads. Square and circular small scale columns with three different slenderness ratios of 5, 6.7 and 10 were adopted. A comprehensive experimental progarmme was then running to measure the load capacity and both lateral and vertical displacements. The failure mode was also monitored for each tested case. The results obtained was compared with the reference column samples (without wire mesh) and with some expressions suggested by ACI Code. The experimental results showed that the most influential parameter on the property of load carrying capacity is the slenderness of column. As the slenderness increases, the load capacity clearly decreases. The use of wire mesh enhanced the capability of column to resist the axial loads due to confinement role provided by such material. The maximum percentage increase in load carrying capacity for the modified columns compared with those for the reference samples was 53% for the circular column at slenderness ratio of 10. The critical path of the failure mode was similar for all of the tested columns and normally began from the top or bottom ends, then, in some cases, passed through the middle zone of the column. A suitable expression was suggested to be used for calculating the modulus of elasticity of the tested column based upon the value of load carrying capacity under compression loads.

关键词： Ferrocement Concrete Columns compression loads Slenderness Ratios

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缺口试件在压缩循环载荷下的疲劳行为研究

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大连理工大学学报 1996年第6期 30-33页

作者： Chen Ruifeng, Chen Haoran, Ren Mingfa ( Research Institute of Engineering Mechanics, DUT ) He Yuting, Fu Xiangjiong ( Northwestern Polytechnical University )

缺口试件在压缩循环载荷下的疲劳行为研究... 详细信息

缺口试件在压缩循环载荷下的疲劳行为研究...

关键词： compression loads cyclic loads cracks residual stress tension

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