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1

Inverse method for a one-stage spur gear diagnosis

Akrout A., Tounsi D., Taktak M., Abbes M. S., Haddar M.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 3

617--628

EN

In this paper, a source separation approach based on the Blind Source Separation (BSS) is presented. In fact, the Independent Component Analysis (ICA), which is the main technique of BSS, consists in extracting different source signals from several observed mixtures. This inverse method is very useful in many fields such as telecommunication, signal processing and biomedicine. It is also very attractive for diagnosis of mechanical systems such as rotating machines. Generally, dynamic responses of a given mechanical system (displacements, accelerations and speeds) measured through sensors are used as inputs for the identification of internal defaults. In this study, the ICA concept is applied to the diagnosis of a one-stage gear mechanism in which two types of defects (the eccentricity error and the localized tooth defect)are introduced. The finite element method allows determination of the signals corresponding to the acceleration in some locations of the system, and those signals may be used also in the ICA algorithm. Hence, the vibratory signatures of each defect can be identified by the ICA concept. Thus, a good agreement is obtained by comparing the expected default signatures to those achieved by the developed inverse method.

2

Effect of camshaft eccentricity and follower backlash on the dynamic behaviour flexible cam mechanism

Tounsi M., Chaari F., Abbes M. S., Fakhfakh A. T., Haddar M.

Diagnostyka

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2010

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nr 2(54)

3-9

EN

A cam follower system is modelled in this work. The equation of motion and the eigenfrequencies are recovered. The computation of the dynamic response is made by mean of combined implicit Newmark-Newton Raphson algorithm. Moreover, dynamic behaviour of the follower train is analysed in presence of an eccentricity in the camshaft and backlash between the follower rods and its guide.

3

Dynamic behavior of a rotor supported by angular ball bearings

Abbes M. S., Hentati T., Maatar M., Fakhfakh T., Haddar M.

Diagnostyka

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2009

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nr 3(51)

3-8

EN

The wide range and large scale usage of rolling bearings indicates their necessity and vital contribution to the performance of modern industries. In this paper, a non linear model, predicting mechanical behavior of the loaded angular ball bearing, have been developed. The dynamic behavior of a rotor supported by two angular ball bearings is analyzed. The finite element method is used and the rotor is decritizied on beam elements. A mathematical modal taking account different sources of non linearity: the Hertzian contact force and the action of all balls on the bearings inner races, is developed. The Newmark algorithm coupled with Newton Raphson iterative method is used to solve the non linear differential equation iteratively.