The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite...The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static effects of the eccentric moving trucks, are significantly smaller than the vehicle-free side, the increase in the road roughness is the most sensitive one among the above influential factors. The results could provide references for the design, static and dynamic response analysis of the similar extra-wide suspension bridges.展开更多
Global effects caused by the detonation of an IED near a military vehicle induce subsequent severe acceleration effects on the vehicle occupants.Two concepts to minimize these global effects were developed,with the he...Global effects caused by the detonation of an IED near a military vehicle induce subsequent severe acceleration effects on the vehicle occupants.Two concepts to minimize these global effects were developed,with the help of a combined method based on a scaled experimental technology and numerical simulations.The first concept consists in the optimization of the vehicle shape to reduce the momentum transfer and thus the occupant loading.Three scaled V-shaped vehicles with different ground clearances were built and compared to a reference vehicle equipped with a flat floor.The second concept,called dynamic impulse compensation(DIC),is based on a momentum compensation technique.The principal possibility of this concept was demonstrated on a scaled vehicle.In addition,the numerical simulations have been performed with generic full size vehicles including dummy models,proving the capability of the DIC technology to reduce the occupant loading.展开更多
电动汽车(electric vehicle,EV)既是交通网的车流负荷,又是电网的用电负荷,它的出行以及充电行为会对交通网和电网的运行规律造成影响。针对电动汽车单体进行随机抽样的传统预测方法,未能从电动汽车群体的移动运行状态考虑,提出了一种...电动汽车(electric vehicle,EV)既是交通网的车流负荷,又是电网的用电负荷,它的出行以及充电行为会对交通网和电网的运行规律造成影响。针对电动汽车单体进行随机抽样的传统预测方法,未能从电动汽车群体的移动运行状态考虑,提出了一种基于交通均衡理论的电动汽车充电负荷预测方法。首先在时间和空间两个维度上,分别对电动汽车和路网进行建模,采用A*算法构建电动汽车出行原目的地(origin-destination,OD)对的有效的路径集。计及用户有限理性,引入分时电价制定了一种计及交通流量约束的充电站电价,并结合随机效用理论与分时电价,建立了半动态交通均衡模型来求解交通流的分配。随后基于组合荷电状态(calculation method of combined state of charge,CSOC)的概率数值计算方法对电动汽车充电负荷进行求解。最后,基于上海市新能源汽车数据,分别以改进的13节点路网和上海市某区域路网分析验证了所提充电负荷预测方法的有效性,结果表明所提方法可以降低充电成本,缓解充电站充电压力。展开更多
基金Project(51278104)supported by the National Natural Science Foundation of ChinaProject(2011Y03)supported by Jiangsu Province Transportation Scientific Research Programs,China+1 种基金Project(20133204120015)supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProject(12KJB560003)supported by Jiangsu Province Universities Natural Science Foundation,China
文摘The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static effects of the eccentric moving trucks, are significantly smaller than the vehicle-free side, the increase in the road roughness is the most sensitive one among the above influential factors. The results could provide references for the design, static and dynamic response analysis of the similar extra-wide suspension bridges.
基金Herr TRDir K.Husing from the German test range WTD-91 GF-440 in MeppenHerr TRDir K.Neugebauer from BAAINBw
文摘Global effects caused by the detonation of an IED near a military vehicle induce subsequent severe acceleration effects on the vehicle occupants.Two concepts to minimize these global effects were developed,with the help of a combined method based on a scaled experimental technology and numerical simulations.The first concept consists in the optimization of the vehicle shape to reduce the momentum transfer and thus the occupant loading.Three scaled V-shaped vehicles with different ground clearances were built and compared to a reference vehicle equipped with a flat floor.The second concept,called dynamic impulse compensation(DIC),is based on a momentum compensation technique.The principal possibility of this concept was demonstrated on a scaled vehicle.In addition,the numerical simulations have been performed with generic full size vehicles including dummy models,proving the capability of the DIC technology to reduce the occupant loading.
文摘电动汽车(electric vehicle,EV)既是交通网的车流负荷,又是电网的用电负荷,它的出行以及充电行为会对交通网和电网的运行规律造成影响。针对电动汽车单体进行随机抽样的传统预测方法,未能从电动汽车群体的移动运行状态考虑,提出了一种基于交通均衡理论的电动汽车充电负荷预测方法。首先在时间和空间两个维度上,分别对电动汽车和路网进行建模,采用A*算法构建电动汽车出行原目的地(origin-destination,OD)对的有效的路径集。计及用户有限理性,引入分时电价制定了一种计及交通流量约束的充电站电价,并结合随机效用理论与分时电价,建立了半动态交通均衡模型来求解交通流的分配。随后基于组合荷电状态(calculation method of combined state of charge,CSOC)的概率数值计算方法对电动汽车充电负荷进行求解。最后,基于上海市新能源汽车数据,分别以改进的13节点路网和上海市某区域路网分析验证了所提充电负荷预测方法的有效性,结果表明所提方法可以降低充电成本,缓解充电站充电压力。
