3rd International Conference on Condition Monitoring of Machinery in Non-Stationary Operations (CMMNO 2013)

General Chairman di 3rd International Conference on Condition Monitoring of Machinery in Non-Stationary Operations (CMMNO 2013), May 8-10, 2013, Ferrara, Ital

Dynamic simulations of the GenC pump behaviour for different oil bulk moduli, relief grooves dimensions and radial plays

Contratto stipulato tramite il Consorzio Ferrara Ricerche con la TRW Automotive GmbH - Dusseldorf (D) - per effettuare simulazioni del comportamento dinamico di pompe GenC al variare dei parametri

Caratterizzazione vibro-acustica sperimentale di invertitori marini

Contratto stipulato tramite il Consorzio Ferrara Ricerche con la Twin Disc Technodrive Srl per la caratterizzazione vibro-acustica sperimentale di invertitori marini

Vibration-based bearing fault detection and diagnosis via image recognition technique under constant and variable speed conditions

This paper addresses the application of an image recognition technique for the detection and diagnosis of ball bearing faults in rotating electrical machines (REMs). The conventional bearing fault detection and diagnosis (BFDD) methods rely on extracting different features from either waveforms or spectra of vibration signals to detect and diagnose bearing faults. In this paper, a novel vibration-based BFDD via a probability plot (ProbPlot) image recognition technique under constant and variable speed conditions is proposed. The proposed technique is based on the absolute value principal component analysis (AVPCA), namely, ProbPlot via image recognition using the AVPCA (ProbPlot via IR-AVPCA) technique. A comparison of the features (images) obtained: (1) directly in the time domain from the original raw data of the vibration signals; (2) by capturing the Fast Fourier Transformation (FFT) of the vibration signals; or (3) by generating the probability plot (ProbPlot) of the vibration signals as proposed in this paper, is considered. A set of realistic bearing faults (i.e., outer-race fault, inner-race fault, and balls fault) are experimentally considered to evaluate the performance and effectiveness of the proposed ProbPlot via the IR-AVPCA method

On the use of cyclostationary indicators in IC engine quality control by cold tests

This paper addresses the use of first- and second-order cyclostationary (CS1 and CS2) tools to process the vibration signals picked up from internal combustion (IC) engines during cold tests. This type of analysis is needed in order to detect and diagnose irregular operations for quality control purposes. The effectiveness of indicators such as Mean Instantaneous Power (MIP), Degree of Cyclostationarity (DCS alpha) and Indicator of Cyclostationarity (ICSnx) in detecting assembly faults has been tested on real signals concerning three faulty conditions: inverted piston, connecting rod with incorrectly tightened screws, connecting rod without one bearing cap. In the past several authors have mainly used cyclostationary metrics for diagnostics purposes in rolling bearings and gear systems. Moreover, a signal model, qualitatively reproducing the features of actual cold test signals, has been formulated and used in order to preliminarily study the influence of signal parameters on the Indicators of Cyclostationarity. The results indicate that the cyclostationary tools - mainly CS2 tools - are effective in detecting and diagnosing all tested faulty conditions. In particular, indicator ICS2x is highly sensitive to faults and it is suitable as pass/fail tool in quality control at the end of the engine assembly line. As a further second-order cyclostationary metric, the MIP is effective for detection, as well for fault identification, since it is able to localize regular and fault events within the engine cycle. In addition DCS alpha effectively characterizes the CS2 periodicities, giving the cyclic order distribution. Since these CS2 tools require a moderate computation cost, they can be considered ready for on-line industrial applications

Condition monitoring of marine couplings by means of vibration analysis techniques

This paper shows the application of some processing techniques for the vibration analysis in working conditions of two different types of marine flexible couplings for boat propulsion. The flexible couplings are mounted between the flywheel of the marine diesel engine and the propeller shaft. The vibration signals are processed in time and frequency domain. Moreover, due to the presence of impulses in the signals, Continuous (CWT) and Discrete Wavelet Transform (DWT) are applied and compared with the conventional time and frequency domain methods. In this work the wavelet analysis is used for the impulse component extraction and the choice of different wavelet functions for this purpose is evaluated. The experimental comparison between two different types of couplings is also given. The results suggest that the wavelet transform techniques are effective to indicate which type of coupling provides a good vibrational behaviour especially in working condition when the angular speed of the propeller shaft is often inverted. Copyright © 2013 by ASME

Simulation of the running in process in external gear pumps and experimental verification

Before marketing external gear pumps are subjected to a running in process to increase their efficiency. However, this is one of the most time-consuming tasks of the entire manufacturing process. Therefore, a mathematical model for optimizing the running in process can be a useful tool for time-to-market reduction. In particular, in this paper a model for the analysis of the dynamic behaviour of external gear pumps, developed by the authors in previous works, is modified and used for simulating the running in process. The modified model is presented and validated via experimental data. A good correlation between simulation and test results guarantees the effectiveness of the model in determining the amount and the distribution of the removed material during the running in process. A meaningful reduction (16%) of the global running in time has been achieved with the introduction of a modified running in process drawn from simulation results