Jia-Hua Yang

Ambient Vibration Test, Modal Identification and Structural Model Updating Following Bayesian Framework

Structural health monitoring (SHM) of civil engineering structures based on vibration data includes three main components: ambient vibration test, modal identification and model updating. This paper discussed these three components in detail and proposes a general framework of SHM for practical application. First, a fast Bayesian modal identification method based on Fast Fourier Transform (FFT) is introduced for efficiently extracting modal parameters together with the corresponding uncertainties from ambient vibration data. A recently developed Bayesian model updating method using Markov chain Monte Carlo simulation (MCMCS) is then discussed. To illustrate the performance of the proposed modal identification and model updating methods, a scale-down transmission tower is investigated. Ambient vibration test is conducted on the target structure to obtain modal parameters. By using the measured modal parameters, model updating is carried out. The MCMC-based Bayesian model updating method can efficiently eva...

Model Updating Based Structural Damage Detection of Transmission Tower: Experimental Verification by a Scaled-Model

Abstract This paper reports a feasibility study on the use of measured vibration data in the detection of damaged braces of a transmission tower by following a model-based approach. A three-dimension finite element model program was developed in MATLAB for the computer modelling of the target transmission tower in this paper. A newly developed substructure-based structural model-updating scheme is employed to identify the stiffness distributions of the target transmission tower utilising the measured natural frequencies and mode shapes. By comparing the identified stiffness distributions of the undamaged and possibly damaged structure, the damage locations and the corresponding damage extents can be estimated. The contributions of this paper are not only on the development of the substructure-based model updating scheme but also on the verification of the proposed methodology through measured data from a scaled transmission tower model under laboratory conditions.