Identificação de Danos Estruturais utilizando Dados no Domínio do Tempo e Critério D-ótimo^†

ABSTRACT

The present work deals with the damage identification problem in mechanical structures from their impulse response. In the adopted model, the structural integrity is continually described by a cohesion parameter and the finite element model (FEM) is used to spatially discretize the displacement and cohesion fields. The damage identification problem is then posed as an optimization one, whose objective is to minimize, with respect to the vector of nodal cohesion parameters, a functional based on the difference between the experimentally obtained impulse response and the corresponding one predicted by an FEM of the structure. The damage identification problem built on the time domain presents some advantages, as the applicability in linear systems with high levels of damping an/or closed spaced modes, and in nonlinear systems. Numerical studies were carried out considering a simply supported Euler-Bernoulli beam. The D-optimal criterion was considered with the aim at determining the optimal position of the displacement sensor. The Differential Evolution (DE) optimization method was considered to solve the inverse problem of damage identification. Numerical analysis were carried out in order to assess the influence, on the identification results, of noise in the synthetic experimental data and of the sensor position. The presented results shown the potentiality of the proposed damage identification approach and also the importance of the optimal experiment design for the quality of the damage identification results.

Keywords:
Structural damage identification; Impulse response function; Finite ElementModel; D-optimal criterion; Differential Evolution