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考虑时效损伤劣化的变参数非线性蠕变损伤模型 被引量:26
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作者 蒲成志 曹平 +1 位作者 张春阳 章求才 《工程力学》 EI CSCD 北大核心 2017年第6期17-27,共11页
应力长期作用下岩体内部损伤不断累积、扩展,导致部分承载单元丧失承载能力,使得岩体内部真实应力强度大于表观应力。该文以流变学理论为基础,将损伤因子引入弹性元件及黏性元件中,给出弹性损伤元件及黏性损伤元件的蠕变特征方程,用以... 应力长期作用下岩体内部损伤不断累积、扩展,导致部分承载单元丧失承载能力,使得岩体内部真实应力强度大于表观应力。该文以流变学理论为基础,将损伤因子引入弹性元件及黏性元件中,给出弹性损伤元件及黏性损伤元件的蠕变特征方程,用以描述持荷过程中由于损伤累积而呈现出蠕变与时间相关的非线性变形特征;然后以弹性损伤元件及黏性损伤元件的蠕变特征方程为基础,给出考虑损伤效应的经典组合模型的蠕变状态方程,并依据稳定蠕变过程中蠕变变形的组成特征,构建了用于描述软岩稳定蠕变的五元件变参数非线性蠕变损伤模型,同时给出了蠕变损伤组合模型的蠕变变形特征方程;最后以江西东乡铜矿砂质页岩稳定蠕变阶段实验数据为基础,分析并验证了蠕变损伤模型在描述软岩非线性蠕变特征方面的准确性及适用性,拟合结果表明:引入损伤因子的蠕变模型元件,能够很好的描述蠕变的时效-非线性特征。 展开更多
关键词 稳定蠕变 损伤因子 损伤元件 时效-非线性 蠕变损伤模型
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Effects of aging parameters on hardness and electrical conductivity of Cu-Cr-Sn-Zn alloy by artificial neural network 被引量:1
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作者 苏娟华 贾淑果 任凤章 《Journal of Central South University》 SCIE EI CAS 2010年第4期715-719,共5页
In order to predict and control the properties of Cu-Cr-Sn-Zn alloy,a model of aging processes via an artificial neural network(ANN) method to map the non-linear relationship between parameters of aging process and th... In order to predict and control the properties of Cu-Cr-Sn-Zn alloy,a model of aging processes via an artificial neural network(ANN) method to map the non-linear relationship between parameters of aging process and the hardness and electrical conductivity properties of the Cu-Cr-Sn-Zn alloy was set up.The results show that the ANN model is a very useful and accurate tool for the property analysis and prediction of aging Cu-Cr-Sn-Zn alloy.Aged at 470-510 ℃ for 4-1 h,the optimal combinations of hardness 110-117(HV) and electrical conductivity 40.6-37.7 S/m are available respectively. 展开更多
关键词 Cu-Cr-Sn-Zn alloy aging parameter HARDNESS electrical conductivity artificial neural network
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Alkaline extraction characteristics of steelmaking slag batch in NH_4Cl solution under environmental pressure 被引量:2
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作者 张慧宁 徐安军 +1 位作者 贺东风 崔健 《Journal of Central South University》 SCIE EI CAS 2013年第6期1482-1489,共8页
In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective ... In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective extraction yield and conversion ratio was systemically focused on. The results show that alkaline earth metal conversion ratio is changed with leaching time and NH4CI concentration by first order exponential, and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH4C1 solution, while leaching temperature and particle size have a linear effect on conversion ratio. Selective extraction yield of calcium is more than 93%, and the value of Mg is less than 5%. Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching, and the case for 38-75 μm slag batch is more obvious than 75 150 μm slag and slag with larger particle size when leaching in 0.4 mol/L NH4Cl solution for 90 rain at 60 ℃. 展开更多
关键词 steel slag alkaline leaching NH4Cl solution selective extraction yield conversion ratio
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Evolution of the Ionospheric Plasma Turbulence over Seismic and Thunderstorm Areas
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作者 Jan Blccki Michel Parrot +3 位作者 Jan Slomiflski Malgorzata Kogciesza Roman Wronowski Sergey Savin 《Journal of Environmental Science and Engineering(A)》 2016年第6期277-285,共9页
The authors report the observation of Extremely Low Frequency (ELF) plasma turbulence registered by DEMETER satellite in the ionosphere over the seismic and thunderstorm areas. The detail analysis of the electric fi... The authors report the observation of Extremely Low Frequency (ELF) plasma turbulence registered by DEMETER satellite in the ionosphere over the seismic and thunderstorm areas. The detail analysis of the electric field fluctuations for the selected strong earthquakes and thunderstorm is presented. Special attention is given to study of the characteristics of the spectra of these variations and searches of the nonlinear effects. This analysis is possible in the time interval when the waveform has been transmitted. Some attempt of this discussion is given in the paper. 展开更多
关键词 EARTHQUAKES IONOSPHERE LIGHTNING plasma turbulence thunderstorms.
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Study on seismic response control of a single-tower self-anchored suspension bridge with elastic-plastic steel damper 被引量:12
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作者 WANG Hao ZHOU Rui +2 位作者 ZONG ZhouHong WANG Chen LI AiQun 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第6期1496-1502,共7页
Elastic-plastic steel damper(EPSD) is a new device controlling seismic responses.The mechanical principle of EPSD was presented and a comparison was conducted between the theoretical formulas and finite element(FE) si... Elastic-plastic steel damper(EPSD) is a new device controlling seismic responses.The mechanical principle of EPSD was presented and a comparison was conducted between the theoretical formulas and finite element(FE) simulation of damper units.The verified force-displacement hysteretic curve of the damper system was obtained with reference to tests.The Nanjing Jiangxinzhou Bridge(NJB) was subsequently taken as the case to investigate the seismic response control effect of EPSDs on single-tower self-anchored suspension bridges.A 3-dimensional FE model of the bridge was established in ANSYS and the dynamic and static analyses of the bridge were conducted,the control effect of EPSDs under different seismic waves was further investigated through nonlinear time-history analysis based on the validated model.Results showed that both the simplified theoretical and FE simulation methods can preferable reflect the mechanical performance of EPSD,and that seismic responses of NJB with EPSDs are better than those with elastic connection device or fluid viscous damper.However,the control effect of EPSDs is influenced by seismic wave characteristics. 展开更多
关键词 elastic-plastic steel damper single-tower self-anchored suspension bridge FE model validation nonlinear time-historyanalysis seismic response control
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