Showing papers in "Mechanical Systems and Signal Processing in 2001"

TL;DR: In this article, it was shown that the spectral correlation can be interpreted as a Fourier transform of the average squared envelope of the signal, which is much easier to obtain directly.

TL;DR: In this article, the limits of the mentioned methodologies are presented by showing their application to bearings affected by different pitting failures on the outer or inner race or a rolling element and subjected to a very low radial load.

TL;DR: In this paper, the authors examined whether acoustic signals can be used effectively to detect the various local faults in gearboxes using the smoothed pseudo-Wigner-Ville distribution.

TL;DR: In this article, the authors apply statistical process control methods referred to as "control charts" to the vibration-based damage detection problem, where residual errors computed from the autoregressive (AR) model and subsequent new data are monitored relative to the control limits.

TL;DR: In this paper, a scheme of using the resonance demodulation technique for early detection of gear tooth cracks is presented, which focuses on the fact that gear tooth crack will produce vibration impacts that would excite the structural resonances when the cracked tooth is engaged.

TL;DR: In this paper, a simplified gear dynamic model was proposed to explore the effect of friction on the resultant gear case vibration, where the model incorporates variations in gear tooth torsional mesh stiffness, developed using finite element analysis.

TL;DR: In this paper, the root mean square, peak value, kurtosis and crest factor were measured through the test duration from accelerometers and acoustic emission sensors, and the results showed that the failure of bearings can result in costly downtime.

TL;DR: In this paper, the sensitivity and robustness of the currently well-accepted techniques: phase and amplitude demodulation, beta kurtosis, and wavelet transform were investigated, and four gear test cases were used: healthy gears, cracked, filed and chipped gears.

TL;DR: In this article, the results of computer simulations and results obtained by laboratory rigs and field practice are compared, and different factors are taken into consideration: design factors, production technology factors, operational factors and change of condition factors.

TL;DR: In this article, a dynamic model for simulating the instantaneous angular speed waveforms on a small four-cylinder diesel engine is presented, and a dynamic analysis of the tangential forces induced by the gas pressure and the vertical imbalance inertial force are calculated and analyzed based on the proposed dynamic model, respectively.

TL;DR: In this paper, a transmissibility matrix between two sets of response functions of a structure is built in either of two ways: (i) from the mobility matrix of the structure or (ii) from test-measured responses only.

TL;DR: In this paper, the use of the proper orthogonal modes of displacements for the identification of parameters of non-linear dynamical structures with an optimisation procedure based on the difference between the experimental and simulated POM.

TL;DR: In this article, a fuzzy linguistic approach to achieve the inclusion of somewhat subjective assessments of maintenance strategies and practices in an objective manner is outlined in order to assist decision makers in the evaluation and selection of maintenance strategy and particular condition-monitoring techniques.

TL;DR: In this article, a self-organising map (SOM) was employed to identify the tool state and a correlation coefficient approach was used to automatically select the best features indicative of the progressive wear of the diamond tools.

TL;DR: In this paper, the state-of-the-art in the area of model updating for non-linear, transient dynamics is reviewed using data from numerical or experimental testbeds.

TL;DR: In this paper, independent component analysis (ICA) is applied to engine acoustic signals to identify the engine noise sources, which decomposes the signals into a number of independent components (ICs) so the individual engine acoustic sources can be studied separately.

TL;DR: In this article, an adaptive network-based fuzzy inference system (ANFIS) is used to detect low-speed rolling-element bearing faults based on discrete wavelet packet analysis (DWPA).

TL;DR: It is quite reasonable for effective fault diagnosis to use non-linear diagnostic methods in addition to the methods currently used, such as orbit portrait, FFT spectra, time–frequency analysis, etc.

TL;DR: In this article, a critical comparison of four stochastic (PEM, 2SLS, LMS, IV) and three deterministic (LS, Prony, ERA) methods for the parametric time-domain identification of vibrating structures from random excitation and noise-corrupted response signals is presented.

TL;DR: A survey of currently available inertia parameter identification methods can be found in this article, where a classification of the identification methods is presented based on the general equations of motion of a rigid body and their simplifications with respect to several linearization steps.

TL;DR: In this paper, the use of multivariate statistical techniques in a two-stage industrial helical gearbox, to detect localised faults by using vibration signals was investigated and explored, where the vibration signals, obtained from a number of sensors, are synchronously averaged and then the multivariate statistics, based on principal components analysis, is employed to form a normal (reference) condition model.

TL;DR: In this paper, a method of detecting transients in mechanical systems by matching wavelets with associated signal is proposed, leading to a development of joint time-frequency-scale distribution, which maximizes the chance for finding similar signal segments from a system under inspection.

TL;DR: The results suggest a rise in unstable behaviour due to the introduction of backlash in robot joints, and a straightforward method for condition monitoring using non-linear dynamics characteristics, based on a classification procedure, is suggested.

TL;DR: In this paper, a comprehensive linear multi stage autoregressive moving average with exogenous excitation (LMS-ARMAX) method for effective multiple-input multiple-output (MIMO) structural dynamics identification in the presence of noise is introduced.

TL;DR: A comparison between cyclostationarity and bilinearity is presented for the first time and a classification method is introduced that allows us to determine if a link between two frequencies is Cyclostationary rather than bilinears.

TL;DR: In this article, cracks were observed in metal beams obtained under controlled fatigue-crack propagation, where the beams were clamped in a heavy vise and struck in order to obtain a clean impulse modal response.

TL;DR: In this article, an inverse method for the assignment of natural frequencies and nodes of normal modes of vibration by the addition of grounded springs and concentrated masses is presented, which relies entirely on measured receptances at the coordinates of the nodes and the modifications.

TL;DR: In this article, an enhanced version of the Wigner-Ville distribution function (WDF) is reported, which is defined by the convolution integral of original WDFs of the input to the system and the system impulse response function.

TL;DR: In this article, the authors discuss the use of frequency-domain criteria for finite element (FE) model correlation and updating, which can be local or global, are either shape or amplitude based.