Showing papers in "Mechanical Systems and Signal Processing in 2000"

TL;DR: In this paper, bearing fault vibrations are modelled as a series of impulse responses of a single-degree-of-freedom system and the model incorporates slight random variations in the time between pulses so as to resemble actual vibration signals.

TL;DR: In this paper, a gear pair affected by a fatigue crack is compared with those obtained by means of the well-accepted cepstrum analysis and time-synchronous average analysis.

TL;DR: In this article, the authors combined the high frequency resonance technique, used for many years in the early detection of failure in rolling element bearings by vibration analysis, is combined with the technique of synchronous averaging.

TL;DR: In this article, a stochastic defect propagation model is established by instituting a lognormal random variable in a deterministic defect propagation rate model, which is calibrated on-line by a recursive least squares (RLS) approach without the requirement of a priori knowledge on bearing characteristics.

TL;DR: In this article, the theory of cyclostationary processes is introduced as a powerful tool for the diagnosis of rotating machines and the spectral correlation function issued from the second-order cyclostarity is an efficient parameter for the early diagnosis of faults in rotating machines.

TL;DR: In this paper, a generalisation of the transmissibility concept for structures with several degrees of freedom is presented, where a transmissability matrix between two sets of response functions is built from any of the mobility matrices of the structure.

TL;DR: In this paper, the authors used modal frequencies in conjunction with mode shapes to identify the existence of bridge damage or deterioration of interest, but it is difficult to isolate damage locations using these modal parameters.

TL;DR: In this paper, a new method for estimating parameters of non-linear parametric models that uses internal feedback to account for nonlinearities is presented, and the method estimates the linear frequency response matrix and nonlinear system parameters at forced and unforced degrees of freedom of general multiple-degree-of-freedom nonlinear systems simultaneously.

TL;DR: In this paper, a symmetrised dot pattern (SDP) method was used to visualize sound signals measured for fans, and through the analysis of sound signals in the time-frequency domain and wavelet analysis, the signal component indicative of a fault was identified.

TL;DR: In this paper, the instantaneous power spectrum (IPS) was used to detect local faults in helical gears under constant speed and load conditions, and it can also indicate the progression of faults under varying load conditions.

TL;DR: In this paper, a control law for friction dampers which maximises energy dissipation instantaneously by controlling the normal force at the friction interface is proposed, and the effect of displacement-and velocity-induced friction dynamics is considered for the design of the control law.

TL;DR: In this paper, the authors apply blind sources separation (BSS) to a test bench where various machines operate simultaneously in order to diagnose each element. But the results indicate that this approach can be successfully applied to these signals for vibration analysis; acoustical analysis is more complex.

TL;DR: In this paper, a three-storey aluminium space frame is modelled using beam elements with unrepresentative rigid joints, and five model-updating experiments are carried out using different sets of updating parameters.

TL;DR: In this paper, a bispectral-based statistical change detection algorithm for rotating machinery health monitoring is presented, which can detect structural defects in rotating machinery components (e.g. bearings and gears) through monitoring of vibration and/or sound emissions.

TL;DR: It is found that, in situations with a moderate or high level of spectral interference, the IWPA method outperforms the IFFT and is even competitive with ESPRIT, which has the lowest computational cost.

TL;DR: In this article, the problem of spalled bearing vibration signal modelling is addressed, based on results mainly obtained by a Time-Frequency Analysis of experimental signals, and classical approaches are discussed and their limitations are pointed out.

TL;DR: In this article, the rotational degree of freedom (rdof) parameters were derived from a new viewpoint by using a well-known technique, the finite-difference formulation, to establish the best rotational data to be used as input in structural coupling analysis.

TL;DR: In this article, a phase difference correction method was developed to correct the frequency and phase of spectrum peak, where the continuous time-domain signal is separated into two segments and fast Fourier translation is carried out for them, respectively.

TL;DR: In this paper, the modal response of a notched, tensioned, steel band undergoing broadband vibration excitation to propagate cracks across the notched area until failure is used as a prognostic observable.

TL;DR: In this paper, the authors presented the first attempt in using the wavelet estimation technique directly on transient data and not on the impulse response estimates obtained via the random decrement technique.

TL;DR: In this paper, the authors defined the concept of symptom reliability for systems in use or in operation, which means that the reliability is based on symptoms of the systems under consideration, and proposed the symptom-dependent hazard functions for their use.

TL;DR: In this paper, a series of seeded fault tests performed on the double-helical gears in a marine gearbox were described and the analysis of the vibration signals measured at two locations on the gearbox for each of five faults was presented.

TL;DR: In this paper, a general methodology is proposed for the optimum selection of DVA parameters so as to guarantee the efficiency of those devices over a previously selected frequency band by using a substructure coupling technique exploring frequency response functions (FRFs).

TL;DR: Conditional time-frequency moments are discussed and applied to the Westland helicopter test data and it is shown that they characterise the faults well and can differentiate between different fault classes.

TL;DR: In this article, the difference between proportional and general viscous damping models is investigated, and it is shown that in the case of proportional damping this orthogonal matrix becomes the identity matrix, which enables a real-valued normalisation of the modal matrix.

TL;DR: In this paper, the authors used reduced interference distributions (RIDs) and scale transforms in the analysis of signals obtained from accelerometers placed strategically on a Westland helicopter transmission for fault detection.

TL;DR: In this article, a unified view of model-based approaches for fault detection and isolation (FDI), taking as a guideline the different levels of the knowledge available about the monitored system, is developed.

TL;DR: In this paper, the authors used two neural networks (to classify acquired data) moderated by an Expert System (based on Taylor's tool life equation) to accurately monitor tool wear with a single machine/tool/material/cutting condition combination and to identify any inconsistencies between the predictions of the neural networks and engineering practice.

TL;DR: In this article, the Karhunen-Loeve decomposition procedure is applied to a system of coupled cantilever beams with non-linear grounding stiffnesses and a non-linearly coupled rods.