Showing papers in "Mechanical Systems and Signal Processing in 2003"

TL;DR: The proposed procedure requires only a few features extracted from the measured vibration data either directly or with simple preprocessing, leading to faster training requiring far less iterations making the procedure suitable for on-line condition monitoring and diagnostics of machines.

TL;DR: In this article, an adaptive wavelet filter based on Morlet wavelet is introduced to detect early fatigue tooth crack in a gearbox with early fatigue teeth crack using the kurtosis maximization principle.

TL;DR: In this paper, a series of numerical simulations on a simple beam are made in order to compare various damage detection methods based on mode shape changes and a generalisation of these methods to the whole frequency ranges of measurement is proposed.

TL;DR: In this article, the authors examined whether acoustic signal can be used along vibration signal to detect the various local faults in gearboxes using the wavelet transform and found that acoustic signals are very affective for the early detection of faults and may provide a powerful tool to indicate the various types of progressing faults.

TL;DR: In this article, the authors present a review and synthesis of the work presented in a developed session of the International Modal Analysis Conference of February 2001 and compare results from typical excitation techniques for large civil engineering structures.

TL;DR: In this article, the effect of the type of morphological operator and of the structuring element on the shape of the envelope is examined, where the basic morphological operators (dilation, erosion, opening, closing) are used for constructing the envelope of impulsive-type periodic vibration signals.

TL;DR: In this article, structural health monitoring of the Z24 bridge in Switzerland was studied using the measurement data from three damage configurations, and the identification of the modal parameters from the response data was automated using stochastic subspace identification technique and the stabilisation diagram.

TL;DR: In this article, the authors have shown that there is a discrete frequency tone within the audible noise spectra, at 147 Hz or BPF/2, which is strongly dependent on the cavitation process and its development.

TL;DR: In this article, a proper orthogonal decomposition is applied on the cross-spectral density functions to extract all of the normal modes contained in the structural responses without suffering from the limitation of the number of response measurement positions.

TL;DR: The detection approach of weak signal based on SR indicates promising future for mechanical fault diagnosis and the weak sinusoid-like signal of lower signal-to-noise ratio can be reliably extracted from heavy noise.

TL;DR: In this article, a method for the localisation and assessment of damage is presented based on the use of mode shape sensitivities to changes in mass or stiffness in the test structure.

TL;DR: In this article, the recognition of faults in toothing during non-stationary start-up and run-down of gear drives is solved by means of the time-frequency analysis.

TL;DR: In this article, a series of full modal surveys are carried out on the bridge before and after applying a number of damage scenarios, tested in the framework of the Brite Euram project SIMCES.

TL;DR: In this article, the authors proposed a damage sensitive feature that takes advantage of the nonlinearities associated with discontinuities introduced into the dynamic response data as a result of certain types of damage.

TL;DR: In this paper, a non-destructive damage-identification technique based on the observed shifts in eigenfrequencies and modeshapes of a structural system is proposed.

TL;DR: In this article, four instantaneous indicators are proposed to characterize the non-linear behavior of mechanical structures from their transient responses, based on the notion of ridges and skeletons introduced for the wavelet processing of signals that are assumed to be defined as a sum of asymptotic amplitude and phase modulated terms.

TL;DR: In this article, a method of damage assessment based on neural networks (NNs) is presented and applied to the Steelquake structure, which is intended to assess the overall damage at each floor in composite frames caused by seismic loading.

TL;DR: The ultimate aim of the work, of which this paper is a part, is to provide a means of on-line automatic monitoring of reciprocating machines using AE without recourse to any additional sensors.

TL;DR: Full utilisation of SVD enables us to pass from multidimensional-non-orthogonalsymptom space, to orthogonal generalised fault space, of much reduced dimension, which seems to be important, as it can increase reliability of condition monitoring of critical systems in operation.

TL;DR: In this article, the use of the chirp vibration responses of an aircraft wing tip was investigated to detect, locate and approximately quantify damage. And the results obtained from the testing led to the concept of a sensor tape to detect damage at joints in an aircraft structure.

TL;DR: Inside the cost action F3 project, one common benchmark was chosen to test several identification methods in order to compare their efficiencies and their specificities, and involves one single local non-linearity coupled with a simple linear structure.

TL;DR: In this article, the singular-value decomposition (SVD) is used to detect the principal features in the data and the SVD standard basis vectors are compared with a transformed-SVD, or TSVD, which reduces the number of features into more compact energy density concentrations.

TL;DR: In this article, numerical results from the application of new stochastic subspace-based structural identification and damage detection and localisation methods to the Z24 concrete bridge of EMPA are discussed.

TL;DR: In this paper, the utility of attractor dimension as a feature was explored and compared with other measures of dimension for signal discrimination in structural health monitoring, and it was concluded that correlation dimension is probably a poor choice of statistic for the purpose of signal discrimination.

TL;DR: In this article, the authors present results of modal identification and damage detection on the Steel-Quake structure using the autoregressive moving average vector and data-driven stochastic subspace methods.

TL;DR: In this paper, a method is presented to identify local non-linear stiffness and damping parameters from dynamic response data by assembling nonlinear two-degree-of-freedom elements into larger linear finite element models.

TL;DR: In this paper, the singular value decomposition (SVD) for a candidate-blocked Hankel matrix using signal subspace correlation (SSC) techniques developed earlier by the author is used.

TL;DR: In this paper, an approach to identify the location and the extent of the damage introduced into the steel frame, using a two-step procedure, is described, where the measured dynamic response of the original undamaged structure was used to generate a reference finite element (FE) model of the structure.

TL;DR: Numerical results from the application of new stochastic subspace-based structural identification and damage detection methods to the steel-quake structure are discussed and some modeshapes are displayed.