基于模型修正的实体车-桥耦合分析系统建立及验证

为将梁格法车-桥耦合分析系统提升至同时考虑结构整体响应及局部应力分析的精细化实体车-桥耦合分析系统，首先，基于最小势能原理推导八节点六面体实体有限单元列式，采用等参插值确定单元的协调位移，引入Wilson非协调位移模式，消除一阶单元在弯曲变形分析中的剪切自锁，提高单元的分析精度和计算效率；采用静/动力分析算例对所构造非协调八节点六面体单元（ICH8）的准确性进行验证；其次，基于车轮与桥面接触实体单元间的位移协调和力的平衡关系，采用非线性分离迭代法建立实体车-桥耦合分析系统，编制自主研发的精细化分析模块；再次，融合Monte-Carlo灵敏度分析与遗传算法构建桥梁实体有限元模型修正方法，并借助现场静载测试结果对目标桥梁实体有限元模型进行修正；最后，联合修正的桥梁实体有限元模型与跑车工况测试结果验证所建立实体车-桥耦合分析系统的准确性。结果表明：由所建立的实体车-桥耦合分析系统得到的桥梁动力响应与实测响应吻合良好，从而验证了该分析系统的可靠性。借助所建立的实体车-桥耦合分析系统，不仅可实现时域内桥梁结构的整体内力分析，同时还可实现桥梁结构的局部应力分析，包括局部构件的应力分布和应力集中等，对当前车-桥耦合振动领域分析工具具有一定的改进和提升。

Development and Validation of Solid Vehicle-bridge Interaction Analysis System Based on Model Updating

To advance the grillage vehicle-bridge interaction analysis system to a more refined solid vehicle-bridge interaction analysis system that can realize both overall and local stress analysis on bridges, an eight-node hexahedral element was first formulated based on the minimum potential energy principle. The compatible displacement was determined using the standard isoparametric interpolations, while the Wilson's incompatible displacement modes were introduced to eliminate shear locking deficiency and improve both the accuracy and efficiency of the element. The resulting incompatible eight-node hexahedral element (ICH8) was then validated through numerical examples. Secondly, the displacement compatibility and force equilibrium relationships at the contact interface were deduced with respect to the ICH8 element. A solid vehicle-bridge interaction analysis system was developed using a nonlinear iteration method. Thirdly, a solid finite element (FE) model updating procedure based on Monte-Carlo sensitivity analysis and the genetic algorithm was proposed to update the solid FE model of the prototype bridge according to the site-measured results. Lastly, the dynamic analysis of the prototype bridge under a moving vehicle was implemented to validate the developed solid vehicle-bridge interaction analysis system. The results show that the bridge dynamic response obtained from the developed analysis system fits well with the site-measured response. More accurate dynamic response of bridge structures under moving vehicles can be directly achieved in the time domain with the developed solid vehicle-bridge interaction analysis system. Moreover, local stress analysis, including the stress distribution and stress concentration, can also be realized. These results can considerably contribute to the improvement of vehicle-bridge interaction analysis.