Significant levels of undesired vibration and noise are inherent in transport and combat vehicles, particularly in helicopters and propeller aircraft. Therefore, it is important to investigate techniques that reduce vibration and noise in the cabin to improve habitability, effectiveness, and safety for passengers. In addition, continuous exposure may lead to long-term physiological effects. In ...

High-speed trains with the maximum speed of 300 km/h, named as Korea Train Express (KTX), have started revenue services since April 2004. Because of the geomorphologic conditions of Korea a large portion of the ‘Kyung-Bu’ line is comprised of tunnels or bridges, which may cause excessive noise in a vehicle. The vibration generated by the trains propagates into the tunnel and the vehicle structu...

The noise levels in the passenger cabin of turbopropeller-driven aircraft are typically higher than the noise levels in comparable turbofan-powered aircraft. The sources of noise in a turboprop aircraft include boundary layer flow noise, structure-borne noise due to engine vibration, and acoustic excitation of the fuselage due to the propeller, with the latter being dominant for most turboprop ...

In this article, the issue of attitude control and active vibration suppression of a nonlinear flexible spacecraft is assessed through piezoelectric patches as actuator and sensors. Two controller loops are applied: the inner loop, to make the panel vibration damped through piezoelectric patches; and the outer loop, to perform spacecraft maneuver using the reaction wheel acting on the hub. An o...

Wiper is a device to wipe out dirt and raindrops from the windscreen. Hence, when a wiper system is operated, it has a potential to generate unwanted noise and vibration level. Reversal is one of the noise and vibration generated during the wiper operations. It is a medium frequency and self excited vibration that is often generated before and vice versa the direction. This leads to poor visibi...

In order to obtain the useful information from the raw data which contain the state data reflecting the structure condition and the noise, de-noising and feature extraction techniques based on Wavelet analysis were studied. An improved wavelet thresholding algorithm to eliminate the noise for vibration signals was proposed. Comparison analysis with other thresholding algorithms shows that the n...

Yuan Wang, Martin J. Turner and W. Terry Hewitt Manchester Computing University of Manchester Manchester, M13 9PL United Kingdom Abstract Using the PHANToM Desktop haptic device, the absolute threshold and difference threshold of finger-hand vibration have been tested and numerically evaluated to assess the usability of this device for general purpose vibration research. In order to highlight t...

The use of vibration signals for internal combustion engines diagnosis is now well established for several applications such as knock detection or valve mechanics behaviour assessment. If standard knock detection can be performed in real time, diagnoses are generally carried out off-line due to algorithm complexity. Our aim was to get some insights on the time-frequency properties of the vibrat...