Sunday, July 22, 2012

VV&UQ for Historic Masonry Structures

What a neat application of verification, validation and uncertainty quantification (VV&UQ) methods! The paper is Uncertainty quantification in model verification and validation as applied to large scale historic masonry monuments.

Abstract: This publication focuses on the Verification and Validation (V&V) of numerical models for establishing confidence in model predictions, and demonstrates the complete process through a case study application completed on the Washington National Cathedral masonry vaults. The goal herein is to understand where modeling errors and uncertainty originate from, and obtain model predictions that are statistically consistent with their respective measurements. The approach presented in this manuscript is comprehensive, as it considers all major sources of errors and uncertainty that originate from numerical solutions of differential equations (numerical uncertainty), imprecise model input parameter values (parameter uncertainty), incomplete definitions of underlying physics due to assumptions and idealizations (bias error) and variability in measurements (experimental uncertainty). The experimental evidence necessary for reducing the uncertainty in model predictions is obtained through in situ vibration measurements conducted on the masonry vaults of Washington National Cathedral. By deploying the prescribed method, uncertainty in model predictions is reduced by approximately two thirds.

  • Developed a finite element model of Washington National Cathedral masonry vaults.
  • Carried out code and solution verification to address numerical uncertainties.
  • Conducted in situ vibration experiments to identify modal parameters of the vaults.
  • Calibrated and validated model to mitigate parameter uncertainty and systematic bias.
  • Demonstrated a two thirds reduction in the prediction uncertainty through V&V.
Keywords: Gothic Cathedral; Modal analysis; Finite element modeling; Model updating; Bayesian inference; Uncertainty quantification

I haven't read the full-text yet, but it looks like a coherent (Bayesian) and pragmatic approach to the problem.


  1. Interesting:
    In the presentation, a brief overview of best-practices for designing calibration experiments will be provided with a particular emphasis on in situ vibration measurements. Specifically, an approach for optimal placement of sensors utilizing an information-based criterion will be discussed to not only reduce the cost and time demands of on-site testing but also the amount of measurement data requiring post-processing.
    Uncertainty Quantification in Model Verification & Validation as Applied to Large Scale Historic Masonry Monuments

  2. Also used in sidings, it is used as a coating for walls and ceilings and for decoration.