Showing papers in "Mechanical Systems and Signal Processing in 1999"

TL;DR: In this paper, a novel approach of stochastic subspace identification is presented that incorporates the idea of the reference sensors already in the identification step: the row space of future outputs is projected into the rowspace of past reference outputs.

TL;DR: In this paper, the output-only modal analysis has typically been approached by applying a peak-picking technique to the auto and cross-powers of the measured responses, resulting in operational deflection shapes and approximate estimates for the resonance frequencies.

TL;DR: In this article, a number of vibration mode shape measurement techniques are described in which the measurement point of a laser Doppler vibrometer (LDV) is continuously scanned over the surface of a sinusoidally excited structure.

TL;DR: In this paper, a remaining life adaptation methodology based on mechanistic modeling and parameter tuning is proposed to estimate defect severity by monitoring the signals generated from rotating bearings and an adaptive algorithm is developed to fine tune the parameters involved in the propagation model by comparing predicted and measured defect sizes.

TL;DR: The generalised S transform is described, a variant of the wavelet transform which allows calculation of the instantaneous phase of a signal, and its application to the decomposition of vibration signals from mechanical systems such as gearboxes for the early detection of failure.

TL;DR: In this article, a technique for structural health monitoring that can detect damage away from a sensor location and during operation of a structure is presented, using vibration measurements to detect damage, but without measuring the excitation force or using a model of the structure.

TL;DR: In this article, the amplitude and phase maps of the wavelet transform are used in conjunction to assess the condition of an instrumented gear test rig, and the phase wavelet map is found to display distinctive features in the presence of a cracked tooth.

TL;DR: A survey of the state-of-the-art interpolation algorithms is presented to ensure that the most appropriate algorithms are identified, and as a result the novel computed order tracking technique introduced in this paper is shown to produce superior results.

TL;DR: In this article, the authors provide a unified approach for conventional and generalised linear models of viscoelastic constitutive behaviour. And they discuss the applicability of fractional derivative concept to the description of material damping.

TL;DR: In this paper, a non-contact vibration measuring system based on a microwave interferometer similar to those used to detect the presence of people in monitored areas is described. But unlike most commercially available far-field noncontact vibration sensors, this system offers other advantages including low cost, quick set-up time, a wide frequency range of response and portability.

TL;DR: In this article, a mutual information measure is used to search a redundant wavelet dictionary for a small set of wavelets that carry meaningful information about machinery faults with these informative wavelets treated as feature extractors, this approach effectively facilitates the diagnosis of machinery faults of a nonstationary nature.

TL;DR: In this article, a committee of neural networks technique was proposed to identify faults in a cantilevered beam, which is substructured into five regions, based on frequency response functions and modal parameters.

TL;DR: In this article, a statistical local approach based on covariance-driven stochastic subspace identification is proposed to monitor the health of a structure in operating conditions (e.g. rotating machinery, civil constructions subject to ambient excitations, etc.) and detect slight deviations in a modal model derived from in-operation measured data.

TL;DR: In this article, the Laplace transform was used to reconstruct cylinder pressure from response vibrations measured externally on a single-cylinder diesel engine, and the results obtained corresponded well with the measured pressure waveforms.

TL;DR: A new simple method using singular value decomposition (SVD) is presented for reducing noise from a sampled signal where the deterministic signal is from a low-dimensional chaotic dynamical system.

TL;DR: In this paper, the theory of normal modes and force appropriation is reviewed and a comparison made of a number of common force appropriation techniques are presented, and comparisons to phase separation results are presented.

TL;DR: In this article, a new strain-gauge-based method for the high-precision vibration measurement of a beam is presented based on the fact that the vibration displacement can be expressed in terms of an infinite number of vibration modes and be related to the measured strains through the strain-displacement relationship.

TL;DR: In this article, the analysis of non-stationary signals of interest in mechanics, and more specifically, more specifically non-parametric time-frequency methods for spectral estimation, has been investigated.

TL;DR: Corrective maintenance, systematic preventive maintenance and conditional maintenance costs are compared and the Weibull law is used to represent reliability and evaluate maintenance costs.

TL;DR: In this article, two methods are proposed in order to determine the optimal or near-optimal positioning of sensors which has to be carried out when vibration tests are being prepared, and the optimal sensors location is proposed on the finite element model associated to the structure to be tested.

TL;DR: In this paper, the mathematical foundations for experimental modal analysis of rotating structures are presented, characterised by non-symmetric and time-varying matrices and solved by modal transformation to derive impulse and frequency response functions, which form the basis of modal identification algorithms in time and frequency domains, respectively.

TL;DR: The application of an artificial neural network to classification of tool wear states in face milling and compare the neural network predictions with observed cutting insert wear states is examined.

TL;DR: An advancement in GA theory is proposed and evaluated to enhance GA search characteristics and the GA-based model refinement process makes use of experimental data to evolve a better correlated finite element model.

TL;DR: In this article, an inverse method for estimating a distributed random excitation from the measurement of the structural response at a number of discrete points is presented, based on a modal model for the structure and a spatial orthonormal decomposition of the excitation field.

TL;DR: In this paper, a finite element analysis of an elastic beam structure subjected to a moving distributed load is presented, where the effects of velocity, mass and train length on the beam's dynamic response are evaluated with respect to the beam stiffness and mass.

TL;DR: An algorithm which consists of a cluster analysis linearisation sub-region division procedure, a linear subset selection routine using an all possible regression algorithm and a genetic algorithm is developed which can be applied to the modelling of non-linear systems using a wide class of model forms.

TL;DR: Three properties of the RandomDec signatures are presented to supplement the mathematical basis for the random decrement technique so that the Randomdec signatures will not be misused in the further system identification.

TL;DR: In this paper, a statistical analysis of errors generated through the process of inertia property identification is performed, and the major factors influencing their accuracy are derived, such as length, area, and volume.

TL;DR: In this paper, a pretest modal model is used together with practical considerations to arrive at the number and location of excitation and response sensors on the test structure, and sensor subsets are selected to facilitate modal parameter estimation.

TL;DR: In this article, a signal processing technique for rotation-related transient signals from a rotating or reciprocating machine is proposed to characterise its instantaneous planar motion, which essentially utilises the directional Wigner distributions (dWDs) defined for the forward and backward pass analytic signals.