The dynamic characteristic analysis model of antenna structures is built,in which the structural physical parameters and geometrical dimensions are all considered as unascertained variables.And a structure dynamic cha...The dynamic characteristic analysis model of antenna structures is built,in which the structural physical parameters and geometrical dimensions are all considered as unascertained variables.And a structure dynamic characteristic analysis method based on the unascertained factor method is given.The computational expression of structural characteristic is developed by the mathematics expression of unascertained factor and the principles of unascertained rational numbers arithmetic.An example is given,in which the possible values and confidence degrees of the unascertained structure characteristics are obtained.The calculated results show that the method is feasible and effective.展开更多
Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduce...Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.展开更多
为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目...为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目标反应谱合成3条耐震时程曲线,利用有限元软件ABAQUS建立柱承式筒仓模型并输入耐震时程曲线,将ETM分析结果与增量动力分析方法(incremental dynamic analysis,IDA)结果进行对比。结果表明:ETM分析结果与IDA分析结果的中位值相匹配,满足筒仓结构抗震性能分析精度要求;筒仓不同支承柱在地震作用下的基底剪力分配情况与储料质量无关,仅取决于支承柱位置;ETM所得的筒仓地震易损性曲线与IDA易损性曲线基本吻合,耐震时程法可作为柱承式筒仓抗震性能分析、预测和评估的高效方法。展开更多
基金the National Defense Science and Technology Research Projects of China (51421060505DZ0155)the National Science Foundation of Shaanxi Province of China (2005A009)
文摘The dynamic characteristic analysis model of antenna structures is built,in which the structural physical parameters and geometrical dimensions are all considered as unascertained variables.And a structure dynamic characteristic analysis method based on the unascertained factor method is given.The computational expression of structural characteristic is developed by the mathematics expression of unascertained factor and the principles of unascertained rational numbers arithmetic.An example is given,in which the possible values and confidence degrees of the unascertained structure characteristics are obtained.The calculated results show that the method is feasible and effective.
基金Projects(51708558,51878673,U1734208,52078485,U1934217,U1934209)supported by the National Natural Science Foundation of ChinaProject(2020JJ5740)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(KF2020-03)supported by the Key Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,ChinaProject(2020-Special-02)supported by the Science and Technology Research and Development Program of China Railway Group Limited。
文摘Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.
文摘为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目标反应谱合成3条耐震时程曲线,利用有限元软件ABAQUS建立柱承式筒仓模型并输入耐震时程曲线,将ETM分析结果与增量动力分析方法(incremental dynamic analysis,IDA)结果进行对比。结果表明:ETM分析结果与IDA分析结果的中位值相匹配,满足筒仓结构抗震性能分析精度要求;筒仓不同支承柱在地震作用下的基底剪力分配情况与储料质量无关,仅取决于支承柱位置;ETM所得的筒仓地震易损性曲线与IDA易损性曲线基本吻合,耐震时程法可作为柱承式筒仓抗震性能分析、预测和评估的高效方法。
