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离散系统动力学的位移变分原理 被引量:2
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作者 李东平 曾庆元 《铁道科学与工程学报》 CAS CSCD 北大核心 2007年第1期68-71,共4页
通过对位移、功、势能和虚位移、虚功等概念的阐述,用变积运算定义了瞬时势能,然后用变积法从达朗贝尔-拉格朗日原理导出位移变分原理。该原理是势能驻值定理在动力学中的发展,也是达朗贝尔-拉格朗日原理的延伸,使动力学问题得到简化。
关键词 动力学 积法 瞬时势能 位移变分原理
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一种基于位移型Gurtin变分原理的逐步积分法 被引量:2
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作者 宋立娜 李勇军 《辽宁工学院学报》 2006年第1期56-59,共4页
本文基于位移型Gurtin变分原理,利用经过空间离散后的只含单重卷积形式的泛函,在局部时间域上采用初位移、初速度和末位移、末加速度同时加入一种非时间步参数的插值函数形式对时间域进行离散,给出了一种计算结构动力响应的逐步积分法... 本文基于位移型Gurtin变分原理,利用经过空间离散后的只含单重卷积形式的泛函,在局部时间域上采用初位移、初速度和末位移、末加速度同时加入一种非时间步参数的插值函数形式对时间域进行离散,给出了一种计算结构动力响应的逐步积分法。对于基于位移型Gurtin变分原理建立的数值算法,采用双参数θ和α能够有效地控制算法的稳定性。文中通过对该计算格式的稳定性研究,确定了合适的非时间步参数α的值以及数值计算时所采用的θ值。精度分析和数值算例表明本文方法具有较高精度,是一种适合于研究结构动力响应问题的时程分析方法。 展开更多
关键词 位移型Gurtin原理 非时间步参数 逐步积 动力响应
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侧限条件下柔性桩复合地基变形分析的能量法
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作者 李义 汤浦 +3 位作者 孟祥康 任华 肖海兵 刘杰 《土木工程》 2021年第11期1129-1135,共7页
为降低软土地基的沉降,提高地基的承载能力,提出了侧向约束复合地基加固技术。同时,基于适当的假设,构造了满足位移边界条件的位移函数。建立了变形影响深度范围内的天然地基和复合地基加固区复合土的总势能方程。基于稳态势能原理,建... 为降低软土地基的沉降,提高地基的承载能力,提出了侧向约束复合地基加固技术。同时,基于适当的假设,构造了满足位移边界条件的位移函数。建立了变形影响深度范围内的天然地基和复合地基加固区复合土的总势能方程。基于稳态势能原理,建立了该系统的位移变分方程,提出了侧向约束复合地基变形分析的近似解析方法。FLAC3D数值模拟结果验证了理论分析方法的合理性。 展开更多
关键词 柔性桩复合地基 荷载–沉降关系 能量法 位移变分方程
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复合材料薄壁杆件非线性扭转分析
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作者 巫祖烈 赵奋 常国强 《重庆交通大学学报(自然科学版)》 CAS 2007年第6期1-6,共6页
考虑几何非线性的影响,建立了在拉、压、弯、扭组合变形下复合材料薄壁杆件理论.重点对杆件进行非线性扭转分析.由给出的等效本构方程和总势能泛函,根据最小势能原理导出了所给问题的平衡控制方程和相应边界条件.讨论了该方程和边界条... 考虑几何非线性的影响,建立了在拉、压、弯、扭组合变形下复合材料薄壁杆件理论.重点对杆件进行非线性扭转分析.由给出的等效本构方程和总势能泛函,根据最小势能原理导出了所给问题的平衡控制方程和相应边界条件.讨论了该方程和边界条件的求解. 展开更多
关键词 复合材料 薄壁杆件 柱壳理论 几何非线性 等效本构方程 位移变分原理
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偏压薄壁杆稳定计算的有限杆元法 被引量:1
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作者 王全凤 《固体力学学报》 CAS CSCD 北大核心 2005年第2期207-210,共4页
根据能量原理,综合三次B样条函数、有限单元法和经典Vlasov薄壁杆理论的优点,提出偏压薄壁杆稳定计算的有限杆元法.推导和求解过程中,同时考虑了截面扭转、翘曲和杆中面上剪应变的影响,可适用求解常用边界条件,任意截面形状的薄壁杆特... 根据能量原理,综合三次B样条函数、有限单元法和经典Vlasov薄壁杆理论的优点,提出偏压薄壁杆稳定计算的有限杆元法.推导和求解过程中,同时考虑了截面扭转、翘曲和杆中面上剪应变的影响,可适用求解常用边界条件,任意截面形状的薄壁杆特征值问题.与经典方法比较显示着该文计算方法的有效性. 展开更多
关键词 薄壁杆 稳定计算 有限杆元法 样条函数 位移变分 临界荷载
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非时间步参数时间有限元法
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作者 赵金城 刘铁林 +1 位作者 朱袆国 吕和祥 《大连大学学报》 1999年第2期1-5,18,共6页
本文基于位移型Gurtin变分原理,对时间域进行离散时,采用具有非时间步参数的话值函数逼近广义节点位移,给出了一种新的计算弹性动力学初值问题的非时间步参数时间有限元法这是一种无条件稳定的计算格式算例表明,本文方法具有计算方... 本文基于位移型Gurtin变分原理,对时间域进行离散时,采用具有非时间步参数的话值函数逼近广义节点位移,给出了一种新的计算弹性动力学初值问题的非时间步参数时间有限元法这是一种无条件稳定的计算格式算例表明,本文方法具有计算方法简便。 展开更多
关键词 非时间步参数时间有限元法 位移型Girton原理 插值函数 弹性动力学
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沿空留巷顶板下沉量计算及分析 被引量:36
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作者 卢小雨 华心祝 赵明强 《采矿与安全工程学报》 EI 北大核心 2011年第1期34-38,共5页
基于支架-围岩整体力学模型,利用位移变分原理研究了沿空留巷时基本顶在给定变形下直接顶的受力、变形情况,探讨了顶板下沉量与巷内、巷旁支护阻力、直接顶厚度、巷道宽度及充填体宽度之间的相互关系.结果表明:巷内支护阻力对顶板下沉... 基于支架-围岩整体力学模型,利用位移变分原理研究了沿空留巷时基本顶在给定变形下直接顶的受力、变形情况,探讨了顶板下沉量与巷内、巷旁支护阻力、直接顶厚度、巷道宽度及充填体宽度之间的相互关系.结果表明:巷内支护阻力对顶板下沉量几乎没有影响;顶板下沉量随巷旁支护阻力的增大而减小;直接顶厚度在2.5 m以内时,顶板下沉量变化不大;而直接顶厚度大于2.5 m时,顶板下沉量随直接顶厚度的增加而显著减少;巷道顶板下沉量随巷道宽度的增加而加大;巷道顶板下沉量随充填体宽度的增大而增大. 展开更多
关键词 沿空留巷 直接顶 位移变分原理 顶板下沉量
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Effects of friction variability on isolation performance of rolling-spring systems 被引量:1
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作者 魏标 王鹏 +3 位作者 杨添涵 戴公连 蒋丽忠 文颖 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第1期233-239,共7页
By taking a rolling-spring isolation system as the study object, the effects of the non-uniform distribution of rolling friction coefficient on its isolation performance were analyzed by a compiled computer program. T... By taking a rolling-spring isolation system as the study object, the effects of the non-uniform distribution of rolling friction coefficient on its isolation performance were analyzed by a compiled computer program. The results show that the errors associated with the structural maximum relative displacement, acceleration and residual displacement due to ignoring the friction variability sequentially grow. This rule is weakened by the spring action, however, the unreasonable spring constant will cause sympathetic vibration. Under the condition of large friction variability, in the calculation of the structural maximum relative displacement and acceleration, the friction variability should be considered. When the structural residual displacement is concerned, the variability of rolling friction coefficient should be fully considered regardless of the friction variability. 展开更多
关键词 rolling-spring structure seismic isolation rolling friction seismic performance
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Slope displacement prediction based on multisource domain transfer learning for insufficient sample data
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作者 Zheng Hai-Qing Hu Lin-Ni +2 位作者 Sun Xiao-Yun Zhang Yu Jin Shen-Yi 《Applied Geophysics》 SCIE 2024年第3期496-504,618,共10页
Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displ... Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data. 展开更多
关键词 slope displacement multisource domain transfer learning(MDTL) variational mode decomposition(VMD) generative adversarial network(GAN) Wasserstein-GAN
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Analysis method of thermal dam deformation 被引量:2
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作者 XU BaoSong LIU BeiBei +2 位作者 ZHENG DongJian CHEN Lan WU CongCong 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第6期1765-1772,共8页
Based on the internal temperature variation of a dam lagging behind the ambient temperature variation,the ambient temperature of continuous variation is disctetized,and the functional expression of the thermal displac... Based on the internal temperature variation of a dam lagging behind the ambient temperature variation,the ambient temperature of continuous variation is disctetized,and the functional expression of the thermal displacement component of the dam caused by single instantaneous temperature variation is obtained.Considering the temporal and spatial distribution law of the ambient temperature and its relation with air and water temperature,the function is expanded into a Taylor series.As a result,the improved thermal displacement component expression for a dam monitoring model is obtained. 展开更多
关键词 concrete dam thermal effect thermal displacement component safety monitoring model
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Discontinuous deformation and displacement analysis: From continuous to discontinuous 被引量:6
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作者 TANG ChunAn TANG ShiBin +1 位作者 GONG Bin BAI HongMei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第9期1567-1574,共8页
A discontinuous deformation and displacement(DDD) analysis method is proposed for modelling the rock failure process. This method combines the rock failure process analysis(RFPA) method(based on finite element method)... A discontinuous deformation and displacement(DDD) analysis method is proposed for modelling the rock failure process. This method combines the rock failure process analysis(RFPA) method(based on finite element method) and discontinuous deformation analysis(DDA) method. RFPA is used to simulate crack initiation, propagation and coalescence processes of rock during the small deformation state. The DDA method is used to simulate the movement of blocks created by the multiple cracks modelled by the RFPA. The newly developed DDD method is particularly suitable for modelling both crack propagation and block movement during the rock failure process because of the natural and convenient coupling of continuous and discontinuous deformation analyses. The proposed method has been used to simulate crack initiation, propagation and coalescence within a slope as well as the block movement during the landslide process. Numerical modelling results indicate that the proposed DDD method can automatically simulate crack propagation and block movement during the rock failure process without degrading accuracy. 展开更多
关键词 rock failure process finite element method discontinuous deformation analysis (DDA) crack propagation slope stability
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Enhanced Raman scattering of graphene on Ag nanoislands 被引量:2
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作者 HU Wei HUANG ZhiYi +2 位作者 ZHOU YingHui CAI WeiWei KANG JunYong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第11期2021-2023,共3页
The effect of Ag nanoislands on the Raman of graphene was investigated in this work.Compared with that on the bare silicon wafer,Raman enhancement was observed in the graphene film that covered on Ag/Si surface with n... The effect of Ag nanoislands on the Raman of graphene was investigated in this work.Compared with that on the bare silicon wafer,Raman enhancement was observed in the graphene film that covered on Ag/Si surface with nanoscale Ag islands,which would be induced by the localized plasmon resonance in Ag nanostructures.The interaction between the graphene sheet and Ag/Si substrate was further studied.The peak shift and line shape of Raman spectroscopy indicated a nonuniform strain distribution in the Ag/Si supported graphene film. 展开更多
关键词 GRAPHENE NANOSTRUCTURE RAMAN
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CONVERGENCE OF CASCADE ALGORITHMS AND SMOOTHNESS OF REFINABLE DISTRIBUTIONS 被引量:3
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作者 SUN QIYU Department of Mathematics, University of Houston, Houston, TX 77204, USA. Department of Mathematics, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore. 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2003年第3期367-386,共20页
In this paper, the author at first develops a method to study convergence of the cascadealgorithm in a Banach space without stable assumption on the initial (see Theorem 2.1), andthen applies the previous result on th... In this paper, the author at first develops a method to study convergence of the cascadealgorithm in a Banach space without stable assumption on the initial (see Theorem 2.1), andthen applies the previous result on the convergence to characterizing compactly supportedrefinable distributions in fractional Sobolev spaces and Holder continuous spaces (see Theorems3.1, 3.3, and 3.4). Finally the author applies the above characterization to choosing appropriateinitial to guarantee the convergence of the cascade algorithm (see Theorem 4.2). 展开更多
关键词 Cascade algorithm Cascade operator Refinable distribution Shift-invariant space Linear independent shifts Stable shifts Fractional Sobolev space
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