Parameters identification of cable stayed footbridges using Bayesian inference
Parameters identification of cable stayed footbridges using Bayesian inference
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DOI：
10.1007/s11012-019-01019-x
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发表时间：
2019-07
期刊：
影响因子：
2.7
通讯作者：
C. Pepi;M. Gioffré;M. Grigoriu
中科院分区：
文献类型：
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作者：
C. Pepi;M. Gioffré;M. Grigoriu
实际结构系统的数值建模是一项非常复杂的任务，主要是由于缺乏对所涉及参数的完整了解。对不确定几何形状、材料特性和边界条件的简化假设使得数值模型响应与实际结构响应不同。有限元 (FE) 模型的改进以获得准确的响应预测可以通过基于振动的 FE 模型更新来实现，该更新使用实验措施来最小化数值和实验模态特征（即固有频率和振型）之间的差异。在此背景下，最近文献中提出了基于贝叶斯定理的概率模型更新程序，以考虑影响结构参数的不确定性及其对结构响应的影响。本文提出了一种有效估计所选模型参数的后验边缘 PDF 的新框架。首先，通过对实际结构系统进行环境振动测试来确定用于模型更新的主要动态参数。其次，开发了第一个数值有限元模型来执行初始敏感性分析。第三，在初始有限元模型上校准基于多项式混沌的代理模型，以显着降低计算成本。最后，估计所选模型参数的后验边际 PDF。使用描述位于特尔尼（意大利中部翁布里亚地区）的弧形斜拉人行桥的有限元数值模型证明了所提出方法的有效性。
Numerical modeling of actual structural systems is a very complex task mainly due to the lack of complete knowledge on the involved parameters. Simplified assumptions on the uncertain geometry, material properties and boundary conditions make the numerical model response differ from the actual structural response. Improvements of the finite element (FE) models to obtain accurate response predictions can be achieved by vibration based FE model updating which uses experimental measures to minimize the differences between the numerical and experimental modal features (i.e. natural frequencies and mode shapes). Within this context, probabilistic model updating procedures based on the Bayes’ theorem were recently proposed in the literature in order to take into account the uncertainties affecting the structural parameters and their influence on the structural response. In this paper, a novel framework to efficiently estimate the posterior marginal PDF of the selected model parameters is proposed. First, the main dynamic parameters to be used for model updating are identified by ambient vibration tests on an actual structural system. Second, a first numerical FE model is developed to perform initial sensitivity analysis. Third, a surrogate model based on polynomial chaos is calibrated on the initial FE model to significantly reduce computational costs. Finally, the posterior marginal PDFs of the chosen model parameters are estimated. The effectiveness of the proposed method is demonstrated using a FE numerical model describing a curved cable-stayed footbridge located in Terni (Umbria Region, Central Italy).