Title: Damage detection through bilinear stiffness estimation in multi-degree-of-freedom frame structures

Authors: Hernán Garrido; Oscar Curadelli

Addresses: Engineering Faculty, National University of Cuyo, Parque Gral. San Martín, Mendoza, ONICET, Argentina ' Engineering Faculty, National University of Cuyo, Parque Gral. San Martín, Mendoza, ONICET, Argentina

Abstract: During its lifetime, the integrity of structures may be affected by exposure to dynamic loads such as earthquakes. In these cases, structures might become damaged, and an early overall evaluation of their integrity is necessary. A particular pattern of damage is that produced by the existence of breathing cracks. These cracks are characterised by their opening and closure during the oscillation of the cracked structural element. In this paper, it is proposed a method for detection of breathing cracks in multi-degree-of-freedom frame structures. The method is based on bilinear stiffness direct estimation, individually for each story of the structure, by using a least-squares approach. The proposed method is demonstrated through a numerical example using the FEM to model a planar structure which presents several breathing cracks. The results suggest that this approach is more sensitive and precise than approaches based on linear stiffness models in detecting and localising damage due to breathing cracks.

Keywords: breathing cracks; damage detection; multi-DOF frame structures; system identification; nonlinear; bilinear stiffness; direct parameter estimation; least-squares; FEM; finite element method; modelling; planar structures; structural integrity.

DOI: 10.1504/IJLCPE.2014.064107

International Journal of Lifecycle Performance Engineering, 2014 Vol.1 No.4, pp.380 - 397

Received: 02 Oct 2013
Accepted: 10 Apr 2014
Published online: 30 Aug 2014 *

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