既有钢管混凝土拱桥的有限元模型修正

Finite Element Model Updating of Existing Steel Pipe Concrete Arch Bridge

有限元模型修正技术最早应用于航空和机械领域,用于自动修正结构模型使数值模型和试验模型相匹配。在过去的十年里,有限元模型修正技术已经被引进到土木工程领域。在既有桥梁的工作状态和使用安全评估中,需要建立能够精确模拟结构目前工作状态的有限元模型。该文以一座既有的钢管混凝土拱桥为例,在参数灵敏度分析的基础上,以结构设计参数为修改参数,构造联合频率和挠度的目标函数,借助ANSYS的优化设计功能对该桥的有限元模型进行修正。修正后模型计算结果和实际测试结果更加接近,其中跨中挠度的最大相对误差只有6%,频率的最大相对误差为9%。修正结果表明:这种联合静动力的模型修正方法物理概念清楚,能充分利用静动力测试数据,经过修正后的有限元模型能够反映该桥的实际工作状态。

The finite element (FE) model updating technology was originally applied in the aerospace and mechanical engineering disciplines to automatically update the structure model to make the numerical model match the experimental model. In the last decade, the finite element model updating technology has been introduced into civil construction engineering. In the assessment of condition and service safety of existing bridges, it is necessary to establish the finite element models which can actually simulate the current working status of the structure. Taking an existing steel pipe concrete arch bridge as an example, based on the analysis of parameter sensitivity and adopting the design parameters as the modifying parameter, the article builds the objective function uniting the frequency with deflection. In this paper, the optimization design function of ANSYS is used to update the finite element model of this bridge. The updated model calculation result and the practically measured result are more closed, in which the maximum relative error of deflection in the span is only 6%, and the maximum relative error of frequency is 9%. The updating result indicates that the physical conception of this combined static and dynamic model updating method is definite and can fully use the static and dynamic testing data. The updated FE model can reflect the real condition of the bridge.