Model Updating Of A Frame Structure Using Penalty Functions Based Procedures.

Abstract

An important requirement in design is to be able to compare experimental results from
prototype structures with predicted results from a corresponding finite element model. In this context,
model updating may be defined as the fit of an existing analytical model in the light of measured
vibration test. After fitting, the updated model is expected to represent the dynamic behavior of the
structure more accurately. An important class of model updating methods is the penalty functions
based approaches (the so-called indirect methods), in which the objective is to maximize the
correlation between the measured and analytical modal model. Because of its nature, the solution
requires the problem to be linearized and optimized iteratively. As the advantages, these methods
allow a wide choice of parameters to be updated that keeps the physical meaning and both the
measured data and the initial analytical parameter estimates may be weighted, which gives the
versatility to the methodology. In this way, this paper presents an indirect based updating study of a
reduced scale three-story plane frame structure constructed and tested at the Laboratory of Structural
Dynamics and Reliability (LDEC) of the Federal University of Rio Grande do Sul (UFRGS), Brazil.
The updated results, presented in this paper, showed great accuracy. The stiffness and mass matrices
were able to keep the original pattern of the finite element model of the structure.