Practical Issues in the Application of Structural Identification
 

Burcu Gunes
    Doctoral Student, Northeastern University

Behnam Arya
    Doctoral Student, Tufts University

Sara Wadia-Fascetti
    Assistant Professor, Northeastern University

Masoud Sanayei
    Associate Professor, Tufts University
 

ABSTRACT

The stiffness parameters of a structural system can be adjusted to match the analytical model's response in order to reproduce the measured test data.  There are a number of practical issues that must be considered for the successful application of parameter estimation to full-scale structures.  These include the design and implementation of the experiment; errors in the mathematical model used for parameter estimation; and errors in the parameter estimation procedure itself.  Modeling error, the uncertainty in the parameters of a finite element model, can have a significant impact on the quality of the resulting parameter estimates.  The impact of modeling error on the resulting parameter estimates is investigated with two scenarios: deterioration and damage.  Deterioration error is modeled as uncertainty in a single parameter distributed across the structure.  Damage error is modeled as localized undetected change in a single parameter and a single element.  Three types of parameters are used in an existing parameter estimation procedure: (1) unknown parameters which are to be estimated, (2) known parameters assumed to be accurate, and (3) uncertain parameters that are assumed known and not to be estimated.  The third group introduces the modeling error into the parameter estimation.  Modeling error is investigated with respect to load and measurement locations, the type of error function used (stiffness-based or flexibility-based), and the selection of unknown parameters to be estimated.  In the example presented, the stiffness-based error function performed much better than the flexibility-based error function.  However, topology of the structure, load and measurement locations, and location of the uncertain parameters with respect to the unknown parameters can have a significant impact on the quality of the parameter estimates.
 

Contact Information:

Prof. S. Wadia-Fascetti (swf@neu.edu)
Dept. of Civil & Env. Engineering
Northeastern University
Boston, MA  02115

Reference:

Gunes†, B., Arya†, B., Wadia-Fascetti, S. and Sanayei, M.  (1999)  “Practical Issues in the Application of Structural Identification.“ in Computational Mechanics in Structural Engineering: Recent Developments. Ed. by F. Cheng and Y. Gu, Elsevier Scientific Ltd. pp. 193-206, 1999.

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