In this paper, two Piezo-Based Rotating Inertial Actuators (PBRIAs) are considered for the suppression of the structure-borne noise radiated from rotating machinery. As add-on devices, they can be directly mounted on a rotational shaft, in order to intervene as early as possible in the transfer path between disturbance and the noise radiating surfaces. generate the appropriate actuation signals...

in this paper, the effects of transverse cracks on rotating shaft were studied. according to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1x and 2x harmonics (first and second order of rotational speed in torsional vibration). this suggests that the application of order analysis...

A Multivariable Control System is designed for an Electromagnetic Bearing and Rotating Shaft System. The Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR) methodology is used to design a robust Model Based Compensator (MBC). The electromagnetic bearing consists of an electromagnetic actuator, operated in magnetic "attractive" force mode, with permanent magnet biased coils. The per...

Unbalance and misalignment are the commonly occurring faults in rotating mechanical systems. These faults are caused mainly due to improper installation or premature failure of the machine components. Detection and diagnosis of faults in rotating machinery is crucial for its optimal performance. In this study artificial neural networks (ANN) and support vector machine (SVM) techniques have been...

In this paper energy method is used to calculate rotor response with loose rotating disk on it. System equation of motion is obtained based on energy method and Lagrange equation. Mathematical modeling of loose disk in a rotor bearing system has resulted in terms similar to unbalance and gyroscopic effect in the system equation of motion. The effect of loose disk axial position and orthotropic ...

Acoustic Emission (AE) is being extensively used as a Non Destructive Technique (NDT) for diagnosis of rotating components. The main theory behind this diagnosis is that while rotation, acoustic energy level of defective portion in rotating element is different. In the present study a signal processing technique is proposed to identify the variation in acoustic signal and results are verified f...

In recent years, as a rule, improvement of the reliability of liquid propellant rockets becomes an international technical problem for built-up of safe space transport systems. The high performance, liquid propellant rocket engines require high-pressured turbopumps to deliver extremely low temperature propellants of liquid oxygen (LO2, boiling point 90 K) and liquid hydrogen (LH2, boiling point...

This paper describes experimental and numerical procedures to estimate friction torque on a rotating shaft due to radial elastomeric seals. Two different test rigs have been built, in order to highlight the relationship between the overall friction and the local behaviour of each lip portion in presence of dynamic eccentricities. A direct measurement has been performed with a rotating shaft mac...

A plain journal bearing is spontaneously unstable above a critical speed and loses much of its load carrying capacity when subjected to a load rotating at about half the speed of the shaft. The almost axially symmetric flow in a compressor can break down at low flow into a rotating pattern of stall cells but only the special case of a single propagating stall cell gives rise to a mechanical cou...