Optical vibration and deviation measurement of rotating machine parts

Abstract

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV).Most rotating machinery parts do not only rotate, they are often subjected to additional excitations. These excitations can lead to minor performance and more wear and finally to the destruction of these components. Hence, it is of interest to have appropriate information about deformations and deviations caused by external excitations. Examples for these effects are processes with cut off wheels grinding wheels, once they are interconnected with different materials, turbine blades under heavy loads of air or fluid as well as brake discs or bearings under operational conditions. In all these applications, analyses of the dynamic behaviour of rotary machine parts are desirable. This can be described by the length and direction of the displacement vector of any material fixed point during its run time.This displacement vector, caused by the external excitations, can be split into two components. Namely into in-plane displacements which take place inside the rotational plane. They are mainly caused by the fluctuating rotational speed, which is always present. Secondly, out-of-plane displacements take place into direction of the rotational axes, mainly caused by lateral loads (Fig. 1).To measure the deformation and vibration of the rotating objects, the displacement vector of any material fixed point between the relaxed position and the position of the same point under load should be determined. This vector can be defined and split relative to body fixed frame, dependent on the measurement methods (Fig. 2).There are several methods to measure the out-of-plane displacement, like holographic interferometry and laser Fig.

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Measurement of weak low frequency pressure signal using stretchable polyurethane fiber sensor for application in wearables

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Implementing an image based control algorithm for an optomechanical image derotator

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