Techno Press
Techno Press

Structural Engineering and Mechanics
  Volume 87, Number 1, July10 2023 , pages 1-18
DOI: https://doi.org/10.12989/sem.2023.87.1.001
 


A novel Metropolis-within-Gibbs sampler for Bayesian model updating using modal data based on dynamic reduction
Ayan Das, Raj Purohit Kiran and Sahil Bansal

 
Abstract
    The paper presents a Bayesian Finite element (FE) model updating methodology by utilizing modal data. The dynamic condensation technique is adopted in this work to reduce the full system model to a smaller model version such that the degrees of freedom (DOFs) in the reduced model correspond to the observed DOFs, which facilitates the model updating procedure without any mode-matching. The present work considers both the MPV and the covariance matrix of the modal parameters as the modal data. Besides, the modal data identified from multiple setups is considered for the model updating procedure, keeping in view of the realistic scenario of inability of limited number of sensors to measure the response of all the interested DOFs of a large structure. A relationship is established between the modal data and structural parameters based on the eigensystem equation through the introduction of additional uncertain parameters in the form of modal frequencies and partial mode shapes. A novel sampling strategy known as the Metropolis-within-Gibbs (MWG) sampler is proposed to sample from the posterior Probability Density Function (PDF). The effectiveness of the proposed approach is demonstrated by considering both simulated and experimental examples.
 
Key Words
    Bayesian model updating; Metropolis-within-Gibbs sampling; model reduction; multiple setups; Transitional Markov Chain Monte Carlo (TMCMC)
 
Address
Ayan Das, Raj Purohit Kiran and Sahil Bansal: Department of Civil Engineering, Indian Institute of Technology Delhi, 110016, Delhi, India
 

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