Passive Vibration Damping of Aluminum by 1-3 Piezocomposites

2004 ◽  
Author(s):  
A. Saigal ◽  
R. Greif ◽  
S. Nakhwa
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Damping Ratio ◽  
Electrical Circuit ◽  
Vibration Damping ◽  
Structural System ◽  
System A ◽  
Damping Characteristics ◽  
Low Volume ◽  
Aluminum Beam

The effective properties of 1-3 piezocomposites are used to examine their passive vibration damping characteristics. An aluminum cantilever beam bonded with 1-3 piezocomposite dampers is modeled by means of “ANSYS” and “SIMULINK” softwares to investigate the dynamic behavior of the system. A method of determining the damping ratio introduced by the piezocomposite damper in conjunction with a simple resistive electrical circuit is established. The effect of volume fraction of the 1-3 piezocomposite on the damping of the system is analyzed. Damping ratio is observed to increase with rising volume fraction. At low volume fractions, the participation of piezoelectric fibers in the load-bearing pattern is to a lesser extent and hence the damping ratio is low. On the contrary as the volume fraction rises, the involvement of piezoelectric fibers increases resulting in higher damping ratios. Given that the inherent material damping in the aluminum beam is 0.0002, the additional damping provided by the bonded piezoelectric strips goes up to a maximum of 0.0042. Finally, the methodology developed in this paper can be used to model any type of vibratory structural system to determine the damping introduced by the piezocomposites.

Preparation and Vibration Damping Characteristics of Wide Frequency Domain PVMQ/IIR Foam Materials

2012 ◽  
Vol 538-541 ◽  
pp. 2298-2303
Author(s):  
Shi Kai Luo ◽  
Guo Fang Ding ◽  
Jing Li Li ◽  
Yan Song Sha ◽  
Qing Min Cheng ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Wide Temperature Range ◽  
Damping Ratio ◽  
Vibration Damping ◽  
Simple Equation ◽  
Structural Damping ◽  
Damping Characteristics ◽  
Damping Materials ◽  
Foaming Technology ◽  
Isoprene Rubber

In this paper, we prepared foaming silicon rubber (PVMQ) /isobutylene-isoprene rubber (IIR) composites with chemical foaming technology. The DMA tests results showed that these foaming materials have effective damping characteristics in a wide temperature range. With the special vibrator, we found that the PVMQ/IIR foams that we prepared were the damping materials which has wide frequency domain, because they can keep high damping ratio in a wide frequency domain. When the preloading was between 1.0 mm and 1.7 mm, the structural damping did not change obviously. According to tests, we found that the damping ratio of these foams was fit to the simple equation .

The Effects of Fiber Volume Fraction on the Vibration Damping Characteristics of Three-Layer-Connected Biaxial Weft Knitted Fabric Reinforced Composite Materials

2012 ◽  
Vol 602-604 ◽  
pp. 49-52
Author(s):  
Jing Xue Liu ◽  
Jia Lu Li
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Damping Ratio ◽  
Vibration Damping ◽  
Knitted Fabric ◽  
Vibration Modes ◽  
Fiber Volume ◽  
Damping Behavior ◽  
Weft Knitted Fabric ◽  
Vibration Parameters

The paper presents an analysis of the vibration damping properties of three-layer-connected biaxial weft knitted fabric (TBWK), which are constituted of carbon fibers as inserted yarns and polyester yarns as knitted yarns impregnated in an epoxy matrix with resin transfer molding (RTM) technique. Damping parameters were investigated using beam test specimens and an impulse technique. Several vibration parameters were varied to characterize the damping behavior in different amplitudes, natural frequencies and vibration modes. The results obtained show that the damping ratio of TBWK composites decreases with the increasing of fiber volume fraction in all the three vibration modes. The vibration test also indicates that the natural frequency of the TBWK composites increases with the increasing of fiber volume fraction (Vf) in all the three modes.

Viscoelastic material damping characteristics of carbon nanotubes based functionally graded composite shell structures

2018 ◽  
Vol 233 (8) ◽  
pp. 1510-1541 ◽  
Author(s):  
Ashirbad Swain ◽  
Tarapada Roy
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Matrix ◽  
Composite Shell ◽  
Volume Fraction ◽  
Vibration Damping ◽  
Functionally Graded ◽  
Element Formulation ◽  
Damping Characteristics ◽  
Stress Resultant ◽  
Viscoelastic Modeling

This work deals with the study of viscoelastic modeling and vibration analysis of functionally graded nanocomposite shell panels where carbon nanotubes are reinforced in the polymer matrix based on the functionally graded distributions of carbon nanotubes. Five types of grading of carbon nanotubes (such as UD, FGX, FGV, FGO, and FGΛ) in the thickness directions have been considered in order to investigate the vibration damping performance of such composite shell panels. A detailed mathematical formulation for the determination viscoelastic properties is presented. The Mori–Tanaka micromechanics in conjunction with weak interface theory has been developed for the mathematical formulations of the viscoelastic modeling of carbon nanotubes based polymer matrix phase. An eight-noded shell element with five degrees-of-freedom per node has been formulated to study the vibration damping characteristics of various panels made by such functionally graded nanocomposite materials. The shell finite element formulation is based on the transverse shear effects as per the Mindlin’s hypothesis, and stress resultant-type Koiter’s shell theory. Impulse and frequency responses of such structures have been performed to study the effects of various important parameters (such as volume fraction of carbon nanotubes, interfacial condition, agglomeration, temperature, geometries of shell panel) on the dynamic responses. Obtained results demonstrate that quick vibration mitigation may be possible using such carbon nanotubes based proposed composite materials.

Multifunctional Nanocomposites With High Damping Performance for Aerospace Structures

2009 ◽  
Author(s):  
F. Liang ◽  
Y. Tang ◽  
J. Gou ◽  
H. C. Gu ◽  
G. Song
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Polymer Matrix ◽  
Composite Laminates ◽  
Polymer Matrix Composites ◽  
Damping Ratio ◽  
Basalt Fiber ◽  
Specific Area ◽  
Vibration Damping ◽  
Damping Characteristics

Polymer matrix composites with reinforcement of carbon nanofibers and carbon nanotubes in the form of paper sheet have shown significant vibration damping improvement compared to pure matrix materials. The large specific area (1000 m2/g) and aspect ratio (>1000) of carbon nanotubes and nanofibers promote significant interfacial friction between carbon nanotubes/nanofibers and a polymer matrix, which causes much higher energy dissipation in the polymer matrix. In this study, a unique concept of manufacturing nanocomposites with carbon nanotube/nanofiber based nanopaper sheets for vibration damping applications has been explored. The new approach includes making carbon nanopaper sheet by the filtration of well-dispersed carbon nanotubes and carbon nanofibers under controlled processing conditions. Subsequently, carbon nanopaper sheets are integrated into composite laminates as surface layer using the vacuum assistant resin transfer molding (VARTM) process. To compare the damping property of laminates constituted by different fibers, three kinds of fibers, including glass fiber, basalt fiber, and carbon fiber are used. For the comparative study, the vibration damping ratios of samples with and without carbon nanopaper sheets are determined. To identify the damping characteristics of each specimen, the Frequency Response Function (FRF) was estimated by a pair of piezoceramic patches: one as an actuator to excite the specimen and the other as a sensor to detect the induced vibrations. From the FRF, the damping ratio of the specimen at each modal frequency of interest was calculated. The experimental results clearly show a significant improvement of vibration damping properties of the nanocomposites plates. This research demonstrates vibration damping enhancement of a polymer matrix via incorporation of carbon nanopaper sheets and provided basic understanding of the damping characteristics for the optimal design and fabrication of high performance damping composites, which have the potential to be used as structural components for different applications.

Sub-Structure Pseudo-Dynamic Response Test of a Pseudo-Elastic Bracing System Made of Shape Memory Alloy

2005 ◽  
Vol 297-300 ◽  
pp. 628-634 ◽  
Author(s):  
Kenichi Ohi ◽  
Jae Hyouk Choi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Original Position ◽  
Small Displacement ◽  
Structural System ◽  
Dynamic Tests ◽  
System A ◽  
Hysteretic Damper ◽  
Bracing System ◽  
Fail Safe

This paper deals with shape memory alloy. As a first step to assess the applicability of this kind of alloy in a structural system, a tension bar made of this kind of alloy that exhibits pseudo-elasticity at room temperature is used herein as a passive bracing system. This paper describes sub-structure pseudo-dynamic tests on pseudo-elastic bracing system with hysteretic damper. A pseudo-elastic bracing system is better to be used with other hysteretic elements such as a hysteretic damper. A damper provides energy dissipation within small displacement levels, and a pseudo-elastic bracing system works in turn as a back-up/fail-safe system when an accidental failure of damper or damper interface occurs, and also it helps to pull back the structure to the original position by uninstalling the damper after earthquake.

LOW CONCENTRATION LIMIT FOR A FLUID FLOW THROUGH A FILTER

1998 ◽  
Vol 08 (04) ◽  
pp. 623-643 ◽  
Author(s):  
SANJA MARUŠIĆ
Keyword(s):  
Asymptotic Behavior ◽  
Fluid Flow ◽  
Volume Fraction ◽  
Periodic Array ◽  
Concentration Limit ◽  
Global Flow ◽  
Low Concentration ◽  
Flow Through ◽  
Low Volume ◽  
Filtration Law

A fluid flow through an ∊-periodic array of obstacles distributed on a hypersurface (filter) is considered. The study of the asymptotic behavior as ∊→0 for two critical sizes of obstacles ∊ and ∊2 gives two different laws describing a global flow. In this paper we study the case of an intermediate obstacle size ∊β, 1 < β < 2 and we prove the continuity of the filtration law in the low-volume fraction limit.

Estimation and Optimization of Vibration Damping Characteristics for Composites Fabricated by Electrodeposition Resin Molding Method

2020 ◽  
Vol 2020 (0) ◽  
pp. 105
Author(s):  
Hiraku TAKISAWA ◽  
Shinya Honda ◽  
Kazuaki KATAGIRI ◽  
Katsuhiko SASAKI ◽  
Ryo TAKEDA
Keyword(s):  
Vibration Damping ◽  
Molding Method ◽  
Damping Characteristics

Analysis of Beam-Like Structures With Displacement-Dependent Friction Forces: Part I — Single-Degree-of-Freedom Model

1995 ◽  
Author(s):  
Wayne E. Whiteman ◽  
Aldo A. Ferri
Keyword(s):  
Dry Friction ◽  
Damping Ratio ◽  
Strong Dependence ◽  
Time Integration ◽  
Single Mode ◽  
Stick Slip ◽  
Friction Forces ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Parameter Values

Abstract The dynamic behavior of a beam-like structure undergoing transverse vibration and subjected to a displacement-dependent dry friction force is examined. In Part I, the beam is modeled by a single mode while Part II considers multi-mode representations. The displacement dependence in each case is caused by a ramp configuration that allows the normal force across the sliding interface to increase linearly with slip displacement. The system is studied first by using first-order harmonic balance and then by using a time integration method. The stick-slip behavior of the system is also studied. Even though the only source of damping is dry friction, the system is seen to exhibit “viscous-like” damping characteristics. A strong dependence of the equivalent natural frequency and damping ratio on the displacement amplitude is an interesting result. It is shown that for a given set of parameter values, an optimal ramp angle exists that maximizes the equivalent damping ratio. The appearance of two dynamic response solutions at certain system and forcing parameter values is also seen. Results suggest that the overall characteristics of mechanical systems may be improved by properly configuring frictional interfaces to allow normal forces to vary with displacement.

Enhancement of vibration characteristics in filament wound FRP composite shafts using nitinol wires

2018 ◽  
Vol 47 (5) ◽  
pp. 377-385 ◽  
Author(s):  
Kannan Murugesan ◽  
Kalaichelvan K. ◽  
M.P. Jenarthanan ◽  
Sornakumar T.
Keyword(s):  
Natural Frequency ◽  
Damping Ratio ◽  
Filament Winding ◽  
Fiber Reinforced ◽  
Content Type ◽  
Fiber Reinforced Plastic ◽  
Damping Characteristics ◽  
Filament Wound ◽  
Reinforced Plastic ◽  
Hollow Shafts

Purpose The purpose of this paper is to investigate the use of embedded Shape Memory Alloy (SMA) nitinol wire for the enhancement of vibration and damping characteristics of filament-wound fiber-reinforced plastic composite hollow shafts. Design/methodology/approach The plain Glass Fiber-Reinforced Plastic (GFRP) and plain Carbon Fiber-Reinforced Plastic (CFRP) hollow shafts were manufactured by filament winding technique. Experimental modal analysis was conducted for plain hollow shafts of C1045 steel, GFRP and CFRP by subjecting them to flexural vibrations as per ASTM standard C747, with both ends clamped (C-C) end condition to investigate their vibration and damping behavior in terms of first natural frequency, damping time and damping ratio. Nitinol wires pre-stressed at various pre-strains (2, 4 and 6 per cent) were embedded with CFRP hollow shafts following same manufacturing technique, and similar experimental modal analysis was carried out by activating nitinol wires. The first natural frequencies of all the shaft materials were also predicted theoretically and compared with experimental measurements. Findings Among the three materials C1045 steel, plain GFRP and plain CFRP, the vibration and damping behavior were found to be the best for plain CFRP. Hence, CFRP shafts were considered for further improvement by embedding nitinol wires at pre-stressed condition. For CFRP shafts embedded with nitinol wires, the damping time decreased; and damping ratio and first natural frequency increased with increase in percentage of pre-strain. In comparison with plain CFRP, 7 per cent increase in first natural frequency and 100 per cent increase in damping ratio were observed for nitinol embedded CFRP shafts with 6 per cent pre-strain. Theoretical predictions of the first natural frequencies agree well with the experimental results for all the shaft materials. Originality/value The effect of nitinol on vibration and damping characteristics of filament wound hollow CFRP composite shafts with different pre-strains has not been studied extensively by the previous researchers. This paper addresses the effect of embedded nitinol wires pre-stressed at three varied pre-strains, that is, 2, 4 and 6 per cent on the vibration and damping characteristics of composite hollow CFRP shafts manufactured by filament winding technique.

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