An efficient computational approach based on substructure methodology is proposed to analyze the viaduct-pile foundation-soil dynamic interaction under train loads.Thetrain-viaductsubsystemissolvedusingthe dynamic sti...An efficient computational approach based on substructure methodology is proposed to analyze the viaduct-pile foundation-soil dynamic interaction under train loads.Thetrain-viaductsubsystemissolvedusingthe dynamic stiffness integration method,and its accuracy is verified by the existing analytical solution for a moving vehicle on a simply supported beam.For the pile foundation-soil subsystem,the geometric and material properties of piles and soils are assumed to be invariable along the azimuth direction.By introducing the equivalent stiffness of grouped piles,the governing equations of pile foundation-soil interaction are simplified based on Fourier decomposition method,so the three-dimensional problem is decomposedintoseveraltwo-dimensionalaxisymmetricfinite element models.The pile foundation-soil interaction model is verified by field measurements due to shaker loading at pile foundation top.In addition,these two substructures are coupled with the displacement compatibility condition at interface of pier bottom and pile foundation top.Finally,the proposed train-viaduct-pile foundation-soil interaction model was validated by field tests.The results show that the proposed model can predict vibrations of pile foundation and soil accurately,thereby providing a basis for the prediction of pile-soil foundation settlement.The frequency spectra of the vibration in Beijing-Tianjin high-speed railway demonstrated that the main frequencies of the pier top and ground surface are below 100 and 30 Hz,respectively.展开更多
文中针对封装结构中焊球模型与基板微通道等模型的跨尺度现象,设计了基于微通道散热技术实现的包含球形栅格阵列(Ball Grid Array,BGA)封装的系统级封装(System in Package,SiP)结构。BGA封装中的焊球尺寸小、数量多,使得封装结构在有...文中针对封装结构中焊球模型与基板微通道等模型的跨尺度现象,设计了基于微通道散热技术实现的包含球形栅格阵列(Ball Grid Array,BGA)封装的系统级封装(System in Package,SiP)结构。BGA封装中的焊球尺寸小、数量多,使得封装结构在有限元建模时的跨尺度问题更为严重。文中生成焊球子结构,并通过算例对焊球子结构建模的准确性进行验证。结果表明:采用子结构方法得到的计算结果不仅与使用常规有限元建模方法得到的结果相差较小,并且还减少了计算时间,为封装结构仿真模型中跨尺度问题提供了方案。展开更多
基金supported by the National Natural Science Foundation of China(Nos.52125803,51988101 and 52008369)。
文摘An efficient computational approach based on substructure methodology is proposed to analyze the viaduct-pile foundation-soil dynamic interaction under train loads.Thetrain-viaductsubsystemissolvedusingthe dynamic stiffness integration method,and its accuracy is verified by the existing analytical solution for a moving vehicle on a simply supported beam.For the pile foundation-soil subsystem,the geometric and material properties of piles and soils are assumed to be invariable along the azimuth direction.By introducing the equivalent stiffness of grouped piles,the governing equations of pile foundation-soil interaction are simplified based on Fourier decomposition method,so the three-dimensional problem is decomposedintoseveraltwo-dimensionalaxisymmetricfinite element models.The pile foundation-soil interaction model is verified by field measurements due to shaker loading at pile foundation top.In addition,these two substructures are coupled with the displacement compatibility condition at interface of pier bottom and pile foundation top.Finally,the proposed train-viaduct-pile foundation-soil interaction model was validated by field tests.The results show that the proposed model can predict vibrations of pile foundation and soil accurately,thereby providing a basis for the prediction of pile-soil foundation settlement.The frequency spectra of the vibration in Beijing-Tianjin high-speed railway demonstrated that the main frequencies of the pier top and ground surface are below 100 and 30 Hz,respectively.
文摘文中针对封装结构中焊球模型与基板微通道等模型的跨尺度现象,设计了基于微通道散热技术实现的包含球形栅格阵列(Ball Grid Array,BGA)封装的系统级封装(System in Package,SiP)结构。BGA封装中的焊球尺寸小、数量多,使得封装结构在有限元建模时的跨尺度问题更为严重。文中生成焊球子结构,并通过算例对焊球子结构建模的准确性进行验证。结果表明:采用子结构方法得到的计算结果不仅与使用常规有限元建模方法得到的结果相差较小,并且还减少了计算时间,为封装结构仿真模型中跨尺度问题提供了方案。
