Abstract:Various types of sandwich beams with viscoelastic cores are currently used in aerospace and automotive industries, indicating the need for simple methods describing the dynamics of these complex structures. In order to understand the effectiveness of the sandwich structures, the dynamics of bare beam with unconstrained and constrained viscoelastic layers are investigated in this study. The viscoelastic layer is bonded uniformly on the beam. The effects of distributed viscoelastic layer treatment on the loss fa… Show more
“…DiTaranto R. [3] and Mead D., Markus S. [4] suggested that for bending and axial vibration the theoretical work on CLD (constrained layer damping) can easily find out. K Kishore Kumar and P Bangarubabu [5] observed that the beams with constrained viscoelastic layer, give higher loss factors values than unconstrained layer. However, the main problem of finding the optimum size of applied constrained layer damping material was not determined.…”
Passive constrained layer damping (PCLD) is nowadays a general method for reducing vibrations. Constrained layer damping (CLD) is a very good technology in terms of reducing vibration energy. This paper deals with optimal damping of first three modes of a thin square cantilever plate by constrained viscoelastic layers which are positioned according to the nodal patterns of the mode. In essence, the CLD patches are cut according to the nodal patterns and then applied on to the bare plate. Thus, this approach uses prior information of the deformation patterns of the plate. The ABAQUS finite element analysis software was used to create viscoelastically damped plate models subjected to forced vibration. The direct steady-state dynamic analysis was used to obtain the frequency response functions from which the resonance frequencies of the models were derived. Vibration control using nodal pattern CLD patches is a better way to apply CLD treatment to a plate. This is because the mode shapes give good predictions of where the maximum strains are in the plate as well as the design and size of the damping patches required. It is believed that the methodology proposed in this research work is capable of providing good results.
“…DiTaranto R. [3] and Mead D., Markus S. [4] suggested that for bending and axial vibration the theoretical work on CLD (constrained layer damping) can easily find out. K Kishore Kumar and P Bangarubabu [5] observed that the beams with constrained viscoelastic layer, give higher loss factors values than unconstrained layer. However, the main problem of finding the optimum size of applied constrained layer damping material was not determined.…”
Passive constrained layer damping (PCLD) is nowadays a general method for reducing vibrations. Constrained layer damping (CLD) is a very good technology in terms of reducing vibration energy. This paper deals with optimal damping of first three modes of a thin square cantilever plate by constrained viscoelastic layers which are positioned according to the nodal patterns of the mode. In essence, the CLD patches are cut according to the nodal patterns and then applied on to the bare plate. Thus, this approach uses prior information of the deformation patterns of the plate. The ABAQUS finite element analysis software was used to create viscoelastically damped plate models subjected to forced vibration. The direct steady-state dynamic analysis was used to obtain the frequency response functions from which the resonance frequencies of the models were derived. Vibration control using nodal pattern CLD patches is a better way to apply CLD treatment to a plate. This is because the mode shapes give good predictions of where the maximum strains are in the plate as well as the design and size of the damping patches required. It is believed that the methodology proposed in this research work is capable of providing good results.
“…The NI-9234 data acquisition (DAQ) system is used to collect the frequency response signals from the accelerometer and are analyzed using LabVIEW software. 10,28,[42][43][44] Results and discussion…”
Section: Fabrication and Dynamic Characterization Of Cgrp-pmc-mrf Cormentioning
confidence: 99%
“…The NI-9234 data acquisition (DAQ) system is used to collect the frequency response signals from the accelerometer and are analyzed using LabVIEW software. 10,28,42–44 Figure 6.(a) Schematic view of forced vibration analysis experimental setup and (b) experimental forced vibration analysis setup.…”
Section: Fabrication and Dynamic Characterization Of Cgrp-pmc-mrf Cormentioning
The semi-active vibration control of sandwich beams made of chopped strand mat glass fiber reinforced polyester resin polymer matrix composite (PMC) and magnetorheological fluid (MRF) core were experimentally investigated in this study. Two-, four- and six-layered glass fiber reinforced polyester resin polymer matrix composites were prepared using the hand-layup technique. The magnetorheological fluid was prepared in-house with 30% volume of carbonyl iron powder and 70% volume of silicone oil. Nine cantilever sandwich beams of varying thicknesses of the top and bottom layers glass fiber reinforced polyester resin polymer matrix composite beams and middle magnetorheological fluid core were prepared. The magnetorheological fluid core was activated with a non-homogeneous magnetic field using permanent magnets. The first three modes, natural frequencies and damping ratios of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams were determined through free vibration analysis using DEWESoft modal analysis software. The amplitude frequency response of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams through forced vibration analysis was determined using LabVIEW. The effect of various parameters such as magnetic flux density, thickness of glass fiber reinforced polyester resin polymer matrix composite layers and magnetorheological fluid core layer on the natural frequencies, damping ratio and vibration amplitude suppressions of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams was investigated. Based on the results obtained, 2 mm thickness top and bottom layers glass fiber reinforced polyester resin polymer matrix composite and 5 mm thickness magnetorheological fluid core sample have achieved a high shift in increased natural frequency, damping ratio and vibration amplitude suppression under the influence of magnetic flux density.
“…Forced vibration analysis using electrodynamic base excitation was performed based on the ASTM E756-05 standard. 10,11,34,35 Figure 20 shows the schematic and photographic view of the experimental forced vibration analysis setup used to determine the excitation amplitude and frequency of the sandwich beams with and without the influence of the magnetic field. The experimental setup consists of 50 kgf electrodynamic shaker, digital switching power amplifier, function generator, single-axis accelerometer sensor, force sensor, NI 9234 DAQ, and LabVIEW 2017 software.…”
Dynamic characterization of silicon carbide particles reinforced Al6082 alloy metal matrix composite sandwich beam with magnetorheological fluid core is experimentally investigated. The study is focused on determining the effect of magnetorheological fluid core on the dynamic behavior of the sandwich structure. The magnetorheological fluid core is enclosed between the top and bottom metal matrix composite beams. The metal matrix composite beams are cast with silicon carbide particles in Al6082 alloy varying from 0 to 20 wt%. The magnetorheological fluid is prepared in-house and contains 30 vol.% carbonyl iron powder and 70 vol.% silicone oil. The free vibration test is conducted to determine the natural frequencies and damping ratio. It is found that the natural frequencies and damping ratio of the sandwich beams increased with an increase in the applied magnetic flux density. The experimental forced dynamic response of sandwich beams is carried out using sine sweep excitation. Vibration amplitude suppression capabilities of the sandwich beams subjected to varying magnetic flux densities are determined. The experimental forced vibration results reveal that metal matrix composite–magnetorheological fluid core sandwich beams have excellent vibration amplitude suppression capabilities.
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