Dynamic characterization of a laminated composite magnetorheological fluid sandwich plate
TL;DR: In this article, the authors investigated the effect of a magnetic field on the variation of the natural frequencies and loss factors of a laminated composite magnetorheological (MR) fluid sandwich plate under various boundary conditions.
Abstract: This study investigates the dynamic properties of a laminated composite magnetorheological (MR) fluid sandwich plate. The governing differential equations of motion of a sandwich plate embedding a MR fluid layer as the core layer and laminated composite plates as the face layers are presented in a finite element formulation. The validity of the developed finite element formulation is demonstrated by comparing the results in terms of the natural frequencies derived from the present finite element formulation with those in the available literature. Various parametric studies are also performed to investigate the effect of a magnetic field on the variation of the natural frequencies and loss factors of the MR fluid composite sandwich plate under various boundary conditions. Furthermore, the effect of the thickness of the MR fluid layer and the ply orientation of the composite face layers on the variation of the natural frequencies and loss factors are studied. The free vibration mode shapes under various boundary conditions of a MR fluid laminated composite sandwich plate are also presented. The forced vibration response of a MR fluid composite plate is investigated to study the dynamic response of the sandwich plate under harmonic force excitations in various magnetic fields. The study suggests that the natural frequency increases with increasing magnetic field, irrespective of the boundary conditions. The reduction in peak deflection at each mode under a harmonic excitation force with variation of the applied magnetic field shows the effectiveness of the MR fluid layer in reducing the vibration amplitude of the composite sandwich plate.
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01 Jan 2017
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2 citations
TL;DR: In this paper , the damping characteristics of two robotic gripper fingers were determined by free vibration analysis using LabVIEW software, and the natural frequency and damping ratio of the PLA gripper finger were determined.
Abstract: Polylactic acid (PLA) is an environmentally friendly, biodegradable, and low-cost thermoplastic material suitable for 3D printing. Complex shapes can be easily produced and hence PLA has been used for many applications. This study presents the damping characteristics of two robotic gripper fingers. The first gripper is composed of a PLA surface layer and a magnetorheological (MR) fluid core and the second gripper is composed of a PLA surface layer bonded to a surface of unimorph piezoelectric Macro Fiber Composite (MFC). The magnetic field is applied by using permanent magnets while the magnetic field strength is varied by changing the distance between the permanent magnets. The electric field is applied by using a micro-amplifier and regulated using data acquisition systems. The natural frequency and damping ratio of the PLA gripper finger are determined by free vibration analysis using LabVIEW software. The damping ratio and vibration amplitude suppression for the PLA grippers was increased as the magnetic field strength changed from 0G to 600G (MR) and as the electric field changed from 0V to 360V (MFC).
1 citations
TL;DR: In this paper , a visco-elastomer sandwich plate with a harmonic distribution of geometrical and physical parameters and distributed supported masses under random base motion loading is studied and an analysis solution with frequency response function and response spectral density expressions of the sandwich plate system is obtained.
Abstract: Vibration control of composite structures with distributed masses under random loadings is a significant issue. Adjustability of dynamic characteristics including response spectrum peaks and valleys is important for structural vibration control. The vibration control design in space contains structure and conformation designs which combination results in periodic composite structures. In the present paper, spatial periodicity control design is proposed. Stochastic response adjustable performance of a visco-elastomer sandwich plate with harmonic distribution of geometrical and physical parameters and distributed supported masses under random base motion loading is studied. Both facial layer thickness and core layer modulus of the sandwich plate are considered as harmonic distribution in length and width directions as well as periodically distributed masses. Partial differential equations of coupling motions of the sandwich plate system are derived and converted into ordinary differential equations for multi-mode coupling vibration. Generalized stiffness, damping, and mass coefficients are functions of the harmonic distribution parameters. An analysis solution with frequency response function and response spectral density expressions of the sandwich plate system is obtained. Numerical results are given to show the response adjustable performance through the harmonic geometrical and physical parameters and distributed masses. The results have a potential application to stochastic vibration control or dynamic optimization design of smart composite structure systems.
1 citations
TL;DR: In this paper , the free vibration analysis of a sandwich plate in contact with quiescent fluid is studied, where the structure is made of an electro-rheological fluid core, and two laminated composite skins.
1 citations
References
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TL;DR: In this paper, the authors review the recent and rapid developments in semi-active structural control and its implementation in full-scale structures, and present an alternative to active and hybrid control for structural vibration reduction.
Abstract: In recent years, considerable attention has been paid to research and development of structural control devices, with particular emphasis on alleviation of wind and seismic response of buildings and bridges. In both areas, serious efforts have been undertaken in the last two decades to develop the structural control concept into a workable technology. Full-scale implementation of active control systems have been accomplished in several structures, mainly in Japan; however, cost effectiveness and reliability considerations have limited their wide spread acceptance. Because of their mechanical simplicity, low power requirements, and large, controllable force capacity, semiactive systems provide an attractive alternative to active and hybrid control systems for structural vibration reduction. In this paper we review the recent and rapid developments in semiactive structural control and its implementation in full-scale structures.
1,179 citations
TL;DR: In this article, a semi-active control of vehicle suspension system with magnetorheological (MR) damper is presented and performance testing is done for this damper with INSTRON machine.
449 citations
TL;DR: A comprehensive survey of electro-rheological (ER) fluids for vibration control can be found in this paper, where the key modes of operation are identified and progress towards a unified approach to visualizing the macroscopic behaviour is summarized.
Abstract: Electro-rheological (ER) fluids are now regarded as one of the most versatile of the materials available for building smart structures and machines. In principle, ER fluids promise an elegant means of providing continuously variable forces for the control of mechanical vibrations. In practice, the development of industrial devices has been hampered by the unavailability of suitable ER fluids. Prompted by recent advances in ER fluid development this paper provides a comprehensive survey of ER devices for vibration control. The key modes of operation are identified and progress towards a unified approach to visualizing the macroscopic behaviour is summarized before presenting a comprehensive survey which includes contributions to the identification of ER fluid dynamics and the application of feedback control. The discussion of results includes some thoughts on future trends.
371 citations
TL;DR: In this article, the transition area between elastic and viscous behavior for a conventional ER fluid and a state-of-the-art magneto-rheological (MR) fluid through the use of oscillatory rheometry techniques is examined.
Abstract: This paper examines the transition area between elastic and viscous behavior for a conventional electro-rheological (ER) fluid and a state-of-the-art magneto-rheological (MR) fluid through the use of oscillatory rheometry techniques. A comparison between the yield behavior (strain and stress) measured for these two different types of controllable fluids is presented. The data obtained for MR fluids represents the initial characterization of the pre-yield properties exhibited by this type of material. Finally, a recommendation as to a key area for future R&D is highlighted.
240 citations
01 Jul 2001
TL;DR: In this article, the modes of operation of MR fluid devices are analyzed and a comprehensive review is presented of the principles, characteristics and engineering applications of the MR fluids devices (especially dampers) studied in the last decade.
Abstract: Magnetorheological (MR) fluids are a class of new intelligent materials whose rheological characteristics change rapidly and can be controlled easily in the presence of an applied magnetic field. The devices based on MR fluids, including dampers, brakes, clutches, polishing devices and hydraulic valves, etc., have a very promising potential future; some of them have been used commercially in engineering applications such as automobiles, polishing machines, exercise equipment, etc. In this paper, the modes of operation of MR fluid devices are analysed. A comprehensive review is then presented of the principles, characteristics and engineering applications of the MR fluid devices (especially dampers) studied in the last decade. Finally, the application prospects of MR fluid devices are discussed.
206 citations