信息融合与响应面联合的渡槽结构模型修正

针对大型渡槽损伤诊断研究中有限元模型精度问题,提出一种基于信息融合与响应面法(response surface method,简称RSM)的有限元模型修正方法,能够兼顾优化目标和参数优化两个环节。以某灌区渡槽为研究对象,建立初始有限元模型,采用试验设计方法构建待修正参数与特征频率的设计空间,经过参数筛选后建立设计样本的响应面模型;引入自适应噪声的完整集成经验模态分解和奇异值分解(complete ensemble empirical mode decomposition with adaptive noise-singular value decompose,简称CEEMDAN-SVD)降噪方法联合方差贡献率数据级融合算法,对正常运行工况下覆盖三跨槽身振测信号进行多通道融合处理以获取完整有效的实测频率,并以此为目标值对响应面模型进行最优化求解,实现多跨渡槽有限元模型的参数优化。结果表明,修正后的有限元模型计算出的频率与实测频率吻合较好,最大误差为-4.38%,有效解决了大型渡槽结构有限元模型的精度问题,为后续结构损伤诊断等仿真研究提供基准模型。

Finite Element Model Updating of Aqueduct Structure Based on Information Fusion and RSM

In order to improve the calculated accuracy of finite element model (FEM) for a large-scale aqueduct damage diagnosis, a FEM updating method based on information fusion and response surface method (RSM) is proposed. The initial FEM method from the aqueduct of one project in china is updated. The parameters of the design space and the frequencies by central composite design (CCD) are built up. Moreover, the dynamic response of the aqueduct under environmental excitation is measured. The test signals that cover three spans of aqueduct are processed to obtain complete and effective frequencies by a signal denoising method based on complete ensemble empirical mode decomposition with adaptive noise-singular value decompose(CEEMDAN-SVD) and an information fusion algorithm based on variance contribution rate. The first four modal frequencies are extracted as the target to optimize the response surface, and the modal frequency of the updated FEM method is compared with the frequency after processing based on structure vibration test. The results show that the calculated frequency of the updated FEM method and the measured frequency are in a good agreement. This study is a successful application of the FEM updating technique on a large-scale aqueduct structure, and provides a baseline evaluation model for the structural damage diagnosis and health monitoring of aqueduct structure.