the problem of crack identification in continuous beam like structures is considered. the cracks’ locations and their depths are identified by employing experimental modal test results performed on the structure. the cracks are modeled using generic elements to include the coupling effects between shear forces and bending moments at the crack section. in the identification procedure eigen- sens...

This paper introduces a set of sensitivity metrics to be used along likelihood-based modal identification methods. In maximum likelihood (ML) estimation theory, the precision of ML point estimates can be measured by the curvature of the likelihood function. This paper presents closed-form partial derivatives, observed information, and variance expressions for discrete-time stochastic state-spac...

This paper presents a new model updating approach for structural damage localization and quantification. Based on the Modal Assurance Criterion (MAC), a new damage-sensitive cost function is introduced by employing the main diagonal and anti-diagonal members of the calculated Generalized Flexibility Matrix (GFM) for the monitored structure and its analytical model. Then, ...

In this paper, a structural damage identification method (SDIM) is developed for plate-like structures. This method is derived using dynamic equation of undamaged/damaged plate, in which local change in flexural rigidity is characterized utilizing a damage distribution function. The SDIM requires to modal data in the intact state and frequency response of damage state where most of vibration ba...

Operational Modal Analysis (OMA) is a powerful tool, widely used in the fields of structural identification and health monitoring, and certainly eligible for identifying the real in-operation behaviour of vehicle systems. Several attempts can be found in the literature, for which the usage of algorithms based on the classical OMA formulation has been strained for the identification of passenger...

A new method of parameter identification based on linear time-frequency representation and Hilbert transform is proposed in this paper to identify modal parameters of linear time-varying systems from measured vibration responses. With Gabor expansion and synthesis theory, measured responses are represented in time-frequency domain and modal components are reconstructed by time-frequency filteri...

An overview of the major development of operational modal identification is presented. It includes four time domain approaches, i.e. NExT-type, ARMAV model-based, stochastic realization-based, stochastic subspace-based methods, and two frequency domain approaches, i.e. FDD-type and output-only LSCF-type methods. The internal relation with traditional modal identification using input/output meas...

A methodology is introduced for the identification of a multi-modal real-valued random variable from a collection of samples. The random variable is seen as a finite mixture of uni-modal random variables. A functional representation of the random variable is used, which can be interpreted as a mixture of polynomial chaos expansions. After a suitable separation of samples into sets of uni-modal ...