润扬大桥修正斜拉索力的基准有限元模型

为了掌握润扬大桥北汊斜拉桥在运营荷载作用下的工作状况和桥梁结构的实际承载力,并为成桥运营健康监测系统提供基准有限元模型,结合该桥的动静载试验,采用自定义钢箱梁主梁截面的脊骨梁整体模型,通过不断修正拉索实参数,使得拉索应力与成桥状态拉索应力实测值相一致.利用Ansys的二次开发功能,编制了相应的宏命令和子结构分析模块.并把计算结果与成桥试验获得的扁平钢箱梁应力和模态频率做了对比分析,计算应力与实测值吻合较好,低阶模态频率相对误差在4%之内,验证了基于实测索力修正模型的正确性,不仅能为成桥健康监测系统提供参考,同时也为今后类似问题的Ansys二次开发提供了相应的思路.

Baseline FE model to revise cable forces in Runyang Cable-Stayed Bridge

Baseline finite element model is necessary for structural health monitoring system of Runyang Cable-Stayed Bridge to analyze the working conditions under various loads and the actual load capacity. Finite element modeling and optimization of Runyang Cable-Stayed Bridge based on measured cable force is presented. A spine finite element model with self-defined beam section is constructed. Then, the measurement results of static and dynamic load testing are taken as reference to optimize the model. The analytical cable force is iteratively updated until the analytical cable stresses are in good agreement with those measured. The optimization algorithm is implemented in Ansys as a novel structure analysis module. After optimization, the analytical results are in good agreement with those measured, including the stress and the modal frequencies. The differences between analytical and measured modal frequencies are less than 4%. This verifies that the optimization philosophy is effective and the optimized finite element model is able to be employed as baseline model in the structural health monitoring. Also, the solution to software development in Ansys for similar research is provided.