A continuing task in engineering is to increase the reliability, availability and safety of technical processes and to achieve these fault diagnosis becomes an advanced supervision tool in the present industries. Vibration in rotating machinery is mostly caused by unbalance, misalignment, shaft crack, mechanical looseness and other malfunctions. The objective of this paper is to propose a model...

There are several non-linear and time variant effects in a rotor-bearing dynamic system. The non-linear characteristics of the rolling element bearing, internal damping, unsymmetrical stiffness of the shaft, cracks on the shaft, and the radial clearance are the typical root causes of these effects [1]. As rotating speeds increase and rotor weights decrease, these non-linear and time variant eff...

Helicopter operations imply Whole-Body Vibration (WBV), primarily due to the motions of the main rotor system. Health effects of WBV in general have primarily been related to the spine and it's related structures. However, many other effects are present, some of them having potential health implications while others may affect safety by acting on the human operator's physiology. METHODS AND DIS...

The advantages of usingmultiple surrogates for approximation and reduction of helicopter vibration are studied. Multiple approximation methods, including a weighted-average approach, are considered so that pitfalls associated with only using a single best surrogate for the rotor blade vibration-reduction problem are avoided. A vibration objective function corresponding to a flight condition in ...

On the rotor comprehensive fault simulation testbed, characteristics of acoustic emission signal of different crack rotors in various depth and conditions are analyzed by the acoustic emission extraction experiment. The noiseeliminating method of the acoustic emission signal was researched by the wavelet packet technique, the characteristics of acoustic emission signal of the rotor crack was al...

This paper reviews recent achievements in the application of active-materials actuation to counteract aeroelastic and vibration effects in helicopters and fixed wing aircraft. A brief review of the induced-strain actuation principles and capabilities is done first. Attention is focused on the smart rotor-blade applications. The induced twist, active blade tip, and active blade flap concepts are...

Turbochargers are most widely used in automotive, marine and locomotive applications with diesel engines. To increase the engine performance nowadays, in aerospace applications also turbochargers are used. Mostly the turbocharger rotors are commonly supported over the fluid film bearings. With the operation, lubricant properties continuously alter leading to different load bearing capacities. T...