Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understandin...Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.展开更多
针对自由表面流动与弹性结构的流固耦合计算效率低、计算耗时长的问题,将流体体积法与基于结构-虚拟弹性体的快速动网格方法相结合,发展了一种适用于自由表面流动的高效流固耦合方法。使用流体体积(volume of fluid,VOF)法对流体自由表...针对自由表面流动与弹性结构的流固耦合计算效率低、计算耗时长的问题,将流体体积法与基于结构-虚拟弹性体的快速动网格方法相结合,发展了一种适用于自由表面流动的高效流固耦合方法。使用流体体积(volume of fluid,VOF)法对流体自由表面进行追踪;将流体域视为虚拟弹性体并构建结构-虚拟弹性体系统,以流固耦合界面的多相流体力为激励求解系统的动力学方程得到结构振动位移和流场网格变形;在每一个时间步内依次求解流体流动、结构变形和流场动网格,实现流固耦合计算。基于发展的方法计算了溃坝水流冲击下弹性挡板的流固耦合响应,得到了溃坝水流的自由液面和弹性挡板的运动行为,结果表明:自由液面演变和弹性挡板振动位移的计算结果与已有算法的结果吻合良好;在同等网格规模下,与已有算法相比本文方法可减少33.3%的计算时间;在水流冲击作用下,弹性挡板向冲击侧小幅弯曲。随后水流沿挡板左侧上升并形成射流,挡板向另一侧大幅弯曲。最后由于两侧流体的阻尼,挡板振幅逐渐衰减。展开更多
为研究双柱式桥墩结构在含大块石泥石流冲击作用下的动力响应特征,基于光滑粒子动力学-有限元(smoothed particle hydrodynamics-finite element method,SPH-FEM)耦合方法,建立泥石流浆体-大块石-双柱式桥墩动态相互作用模型,分别从泥...为研究双柱式桥墩结构在含大块石泥石流冲击作用下的动力响应特征,基于光滑粒子动力学-有限元(smoothed particle hydrodynamics-finite element method,SPH-FEM)耦合方法,建立泥石流浆体-大块石-双柱式桥墩动态相互作用模型,分别从泥石流冲击特征、桥墩结构应变和冲击力时程等方面,分析泥石流冲击下双柱式桥墩的动力学行为,探讨了不同特性泥石流对桥墩承灾破坏特征的影响.结果表明:所提出的数值分析方法可以较好地模拟泥石流冲击、沿桥墩绕流及流出的整个分布过程;泥浆冲击桥墩底部会出现明显的绕流现象,上游的桥墩柱体所受冲击力远大于下游;受块石冲击的桥墩底部承受较大的横向冲击力,导致出现较大应变,甚至混凝土脱落;桥墩所受冲击力与泥石流的冲击速度和大块石直径都呈正相关;夹杂着大块石的泥石流对桥墩的冲击力远大于仅有浆体的冲击力,是造成桥墩破坏的主要因素.研究成果有助于理解泥石流多发区双柱桥墩的冲击灾变机制,并为其抗冲击设计提供科学依据.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
基金financial support from the China Postdoctora Science Foundation(project No.2021M690406)financial supports from the National Natural Science Foundation of China(project No.51708521,51778183)。
文摘Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.
文摘针对自由表面流动与弹性结构的流固耦合计算效率低、计算耗时长的问题,将流体体积法与基于结构-虚拟弹性体的快速动网格方法相结合,发展了一种适用于自由表面流动的高效流固耦合方法。使用流体体积(volume of fluid,VOF)法对流体自由表面进行追踪;将流体域视为虚拟弹性体并构建结构-虚拟弹性体系统,以流固耦合界面的多相流体力为激励求解系统的动力学方程得到结构振动位移和流场网格变形;在每一个时间步内依次求解流体流动、结构变形和流场动网格,实现流固耦合计算。基于发展的方法计算了溃坝水流冲击下弹性挡板的流固耦合响应,得到了溃坝水流的自由液面和弹性挡板的运动行为,结果表明:自由液面演变和弹性挡板振动位移的计算结果与已有算法的结果吻合良好;在同等网格规模下,与已有算法相比本文方法可减少33.3%的计算时间;在水流冲击作用下,弹性挡板向冲击侧小幅弯曲。随后水流沿挡板左侧上升并形成射流,挡板向另一侧大幅弯曲。最后由于两侧流体的阻尼,挡板振幅逐渐衰减。
文摘为研究双柱式桥墩结构在含大块石泥石流冲击作用下的动力响应特征,基于光滑粒子动力学-有限元(smoothed particle hydrodynamics-finite element method,SPH-FEM)耦合方法,建立泥石流浆体-大块石-双柱式桥墩动态相互作用模型,分别从泥石流冲击特征、桥墩结构应变和冲击力时程等方面,分析泥石流冲击下双柱式桥墩的动力学行为,探讨了不同特性泥石流对桥墩承灾破坏特征的影响.结果表明:所提出的数值分析方法可以较好地模拟泥石流冲击、沿桥墩绕流及流出的整个分布过程;泥浆冲击桥墩底部会出现明显的绕流现象,上游的桥墩柱体所受冲击力远大于下游;受块石冲击的桥墩底部承受较大的横向冲击力,导致出现较大应变,甚至混凝土脱落;桥墩所受冲击力与泥石流的冲击速度和大块石直径都呈正相关;夹杂着大块石的泥石流对桥墩的冲击力远大于仅有浆体的冲击力,是造成桥墩破坏的主要因素.研究成果有助于理解泥石流多发区双柱桥墩的冲击灾变机制,并为其抗冲击设计提供科学依据.
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.
