The goal of this study is investigating reduction of residual stresses from welding carbon steel plates through vibrationstress reliefmethod vs. thermal method. In order to carry out the required experimental tests, carbon steel plates were welded together under specific conditions as samples. Some of the samples were vibration stress relieved, some were thermal stress relieved while the rest r...

In this study, a characterization of hysteresis in a piezoceramic stack actuator similar to those employed in an actively controlled flap (ACF) system is performed to assess the effects of hysteresis on system performance. The effect of unmodeled actuation hysteresis may significantly reduce vibration and noise reduction capabilities. A hysteresis model based on the classical Preisach model has...

A computational study of helicopter vibration and rotor shaft power reduction is conducted using activelycontrolled trailing-edge flaps (acfs), implemented in single and dual flap configurations. Simultaneous vibration reduction and performance enhancement is demonstrated under level flight condition at high advance ratios, where dynamic stall effects are significant. Power reduction is achieve...

OBJECTIVES Operation of handheld power tools results in exposure to hand-arm vibrations, which over time lead to numerous health complications. The objective of this study was to evaluate protective equipment and working techniques for the reduction of vibration exposure. METHODS Vibration transmissions were recorded during different work techniques: with one- and two-handed grip, while weari...

today there are different vibration isolators used in industries according to the weight and excitation frequency of the machines which have vibration. one of them is air spring which is in two types: convoluted air spring and membrane air spring. convoluted air springs are used to control vibrations in low frequency (usually lower than 10 hz) and the membrane ones are used in high frequency (u...