To study on the characteristics of the vibration signals of coal and stone hitting the armor plate during caving, a hybrid algorithm based on first order forward difference and wavelet transform modulusmaxima method is presented which can be used in the longwall top coal face. First, in order to reduce the noise interference, the pre-processing of the vibration signals is done by the first orde...

A nonlinear optimal control method is developed for magnetostrictive actuators used to actively attenuate plate vibration. Significant improvements in vibration control can be achieved when the magnetostrictive actuators are driven at moderate to high field levels. This results in nonlinearity and hysteresis which cannot be effectively compensated using linear control theory. This issue is addr...

We will review some of the recent advances in the field of acoustic and elastic metamaterials. These research fields became hot topics in last few years with an increasing number of papers that grows almost exponentially. The interest on these artificial structures arouses because of their potential application in designing novel devices for sound and vibration control. Their applications cover...

This chapter deals with the vibration attenuation or vibration suppression by means of feedback control techniques applied to decrease the dynamic response of a rotor assumed as active magnetic dynamic damping which is common in rotating machinery supported by active magnetic bearings. Position control systems applied on active magnetic bearings are using sometimes nonlinear robust control tech...

An adaptive control system has been developed that may be used for active noise and vibration control problems involving one-dimensional propagation. Based on the least-mean-squares (LMS) algorithm, the adaptive controller performs both system identification and control in real time, without the need for a priori measurements of the system. Since the controller is adaptive in nature, it is poss...

natural hazards such as earthquakes have threatened the life of human beings during the history.as a consequence, the vibration mitigation of structures has caught great importance. activecontrol of structures is one of the rapidly emerging areas in the concept of structural control. thispaper presents a control method to deal with this subject when the dynamics of the structure ishysteretic an...

Periodic composite ultrasonic transducers offer many advantages but the periodic pillar architecture can give rise to unwanted modes of vibration which interfere with the piston like motion of the fundamental thickness mode. In this paper, viscoelastic loss is incorporated into a three-dimensional plane wave expansion model (PWE) of these transducers. A comparison with experimental and finite e...

Structural biological materials have developed heterogeneous and hierarchical architectures that are responsible for the outstanding performance to provide protection against environmental threats including static and dynamic loading. Inspired by this observation, this research aims to develop new material and structural concepts for broadband vibration mitigation. The proposed composite materi...

Vibration-reducing (VR) gloves are commonly used as a means to help control exposures to hand-transmitted vibrations generated by powered hand tools. The objective of this study was to characterise the vibration transmissibility spectra and frequency-weighted vibration transmissibility of VR gloves at the palm of the hand in three orthogonal directions. Seven adult males participated in the eva...