重型车辆与桥梁耦合振动及桥梁冲击系数的数值模拟研究

Numerical Simulation of Bridge-and-heavy-vehicle Coupling Vibration for the Impact Factor Study

为了更合理地评估桥梁在重型车辆作用下的耦合动力响应,在有限元软件LS-DYNA的平台上,根据车桥振动实验数据,建立了具有11个自由度的3轴重型车辆和桥梁上部结构的车桥耦合系统有限元模型。对桥梁模型进行了模态分析,并对车桥耦合振动的三个工况进行了数值模拟,所得结果与实测数据一致,验证了有限元模型的合理性、可靠性。进一步利用该有限元模型进行车桥耦合体系参数分析,选择了车辆运行速度,桥梁桥台搭板的沉降以及桥梁跨度进行桥梁冲击系数的参数敏感性研究。参数分析结果表明:冲击系数整体上随车辆速度的增大而增大,同时有局部极大值的存在;冲击系数随桥台搭板沉降量的增大而增大;冲击系数呈现随桥梁跨度的增大而增大的趋势。

In order to efficiently evaluate the dynamic response of bridge under passage of vehicles , the super-structure of a bridge coupled with an heavy vehicle model of 11 degrees of freedom with three axles was devel-oped by using LS-DYNA software based on available field tests .To validate reliability and efficiency of the fi-nite element （ FE） models and the corresponding algorithm , analyses were carried out and three testing cases were selected for comparison .Good correlation between FE and experimental results confirms that the FE mod-el is reliable for parametric studies .Three parameters including moving velocity of vehicle , the settlement of approach slab and the span length of the bridge , which has influence on the impact factor , were investigated . Numerical results show that impact factor increases with velocity while may reach its local maximum somehow . It goes up with the increase of approach slab settlement .It has a tendency to increase with the increase of bridge span length .