Showing papers in "Mechanical Systems and Signal Processing in 1989"

TL;DR: A new theory of spectral analysis for non-linear systems is introduced which consists of estimating the parameters in a NARMAX model description of the system and then computing the generalised frequency response functions directly from the estimated model.

TL;DR: In this article, the identification results obtained from a study on a Leyland TL11 turbocharged, direct injection diesel engine are presented, and two sets of data corresponding to low and high engine speed tests, which were recorded from experimental trials on the engine, are analysed.

TL;DR: Interpolation by digital computer provides an alternative to the phase-locked frequency multiplier for the calculation of the time domain average of gear vibration signals as discussed by the authors, but it requires longer calculation times.

TL;DR: In this paper, the interpretation and properties of the non-linear frequency response functions are discussed and illustrated by example, and new methods of parametric spectral analysis for a wide class of nonlinear systems were introduced.

TL;DR: In this paper, a wave propagation model was developed to model the standing wave pattern in an impedance tube, and the acoustic impedance of a test specimen was calculated from a best fit of this model to pressure measurements obtained along the impedance tube centerline.

TL;DR: In this paper, a new analysis method which uses fast Fourier transform (FFT) spectra, and combines the ordinary spectra of rotor vibration both in horizontal and vertical directions, is described Since it can provide much more information about rotor vibration behaviour, they introduced it into the diagnostic practice of some oil refineries and chemical plants in China.

TL;DR: In this article, the implementation of the force-state mapping approach to the identification of single and multi-degree-of-freedom non-linear systems is considered, and a method for identifying the type and location of discrete nonlinear elements in a lumped-parameter system is presented.

TL;DR: In this article, the authors presented a method of adjusting the parameters of the mathematical model of a mechanical structure using test data, based on a minimum variance estimator for the unknown mass and stiffnes parameters, using natural frequency and mode shape information.

TL;DR: In this article, the problem of determining the best structural modifications is cast in the framework of mathematical programming, by defining a suitable optimisation problem, which avoids any identification process aimed at the creation of either a modal or a physical model of the structure.

TL;DR: In this paper, the application of the pattern recognition technique for process monitoring in end milling is discussed, where cutting forces, torque, and spindle vibrations are monitored during machining, and are used to generate several signal features.

TL;DR: In this paper, an investigation into the problems of ball mill pinions is presented, where pitch measurements and vibration analysis are conducted to find a relationship between vibration signals and the errors.

TL;DR: In this paper, the authors used the instantaneous envelope and phase of a system impulse response, derived from the complex signal formed by the impulse response itself and its Hilbert transform, for damping factor evaluation.

TL;DR: In this paper, a method to avoid these difficulties is proposed whereby simple and selective structural modifications are introduced allowing the separation of neighboring eigenvalues, where the Jacobian of the eigensolutions is replaced by the Jacobians of the free or forced responses.

TL;DR: In this paper, the distributions of AE spectra generated in earlier work are first analysed, and the results indicate departure from the assumptions, although the lack of normality was not too severe.

TL;DR: In this paper, the modal parameters are derived from the parameters of the vector ARMAX based upon the principle of impulse response invariance, and the procedures are used to analyse a set of simulation data of a three degree of freedom system.

TL;DR: In this paper, a new approach for the modal identification of lightly damped structures is proposed, being derived from, and a particular case of, the Rational Fraction Polynomial Method.

TL;DR: In this paper, a method to detect and identify non-linear dynamic behavior of single-degree-of-freedom (SDOF) systems is presented based on the characteristic evolution of the least squares equivalent damping and stiffness as a function of the velocity and the displacement respectively.

TL;DR: In this paper, an original parametric estimation algorithm in the frequency domain, called ELiS (Estimation of Linear Systems) was used in the field of modal analysis, taking into account the disturbing (measurement) noise on the input as well as on the output of the device under test.

TL;DR: In this paper, it was shown that the estimation of the AR parameters of an ARMA model is identical to the asymptotically unbiased estimate using modified Yule-Walker equation for ARMA (n, n −1).

TL;DR: In this article, it is shown that the behavior of mechanical elastic systems under dynamic actions can be modelled with difference equations which reduce to a very simple form when one-input or free vibration cases are considered.

TL;DR: In this article, a pressure-limited hydraulic damper is proposed to achieve variable damping within a vibration isolation system by limiting the pressure differential across the damper piston, using pressure relief valves.

TL;DR: In this article, the authors employ three versions of the maximum entropy method (MEM) and a version of the MLM to estimate the transfer functions among several places of a vibrating structure and use these transfer functions to resolve the modal shapes of the structure.

TL;DR: In this paper, a method has been developed to enhance the applicability of automatic pattern recognition to the monitoring of mechanical systems by reducing the size of the defect-classification databases through the use of signal reconstruction.

TL;DR: In this paper, a method to distinguish between structural and computational modes for modal data estimated with oversized least squares time domain models is developed based on the convergence and stationarity of the z-plane poles as the algorithm processes subsequent points of the time domain arrays.

TL;DR: In this paper, a dynamic cutting force model for turning of slender workpieces, as well as experimental results related to the frequency response of the workpiece in turning are presented, based on a flexible workpiece and rigid machine tool, and a workpiece displacement dependent cutting force.

TL;DR: In this article, the design of a noise canceer coupled with model-based signal processing techniques to solve the enclosed space detection problem using seismic measurements is discussed, which leads to a multichannel noise cancelling solution.

TL;DR: A frequency analysis of an optimal smoothing and differentiating filter based on a dynamic programming method and the method of generalised cross-validation provides a filter that automatically selects the optimal cutoff frequency.