Identification of damping and stiffness of smart structures incorporating ER fluids

Mahjoob, M. J.; Martin, H. R.; Ismail, F.

doi:10.1016/0003-682x(94)00046-x

Cited by 14 publications

(7 citation statements)

References 12 publications

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“…In the case of a small vibration amplitude, linear approximation can be reasonable; however, when the displacement is larger than the thickness of the beam, this approximation may produce a significant error. In order to meet this condition, the experiment is carried out by imposing a very small disturbance force to the structure in such a way that tip displacement remains under the suggested bound in the standard (Leng et al, 1995(Leng et al, , 1997Mahjoob et al, 1995). Furthermore ER fluid properties have been significantly enhanced over recent years.…”

Section: Optimal Viscoelastic Layer Identificationmentioning

confidence: 99%

“…Various investigations (Leng et al, 1995(Leng et al, , 1997 have been conducted for characterization of ERFs and viscoelastic materials. Mahjoob et al (1995) used modal testing of composite beams for different modes to achieve information about dynamic characteristics of viscoelastic layers in the pre-yield regime. The complex modulus of the ERF layer was identified based on the Mead and Markus formulation Markus, 1969, 1970) and experimental results.…”

Section: Introductionmentioning

confidence: 99%

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Optimal parameters estimation and vibration control of a viscoelastic adaptive sandwich beam incorporating an electrorheological fluid layer

Allahverdizadeh

Mahjoob

Nasrollahzadeh

et al. 2013

Journal of Vibration and Control

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The complex shear modulus of an electrorheological (ER) adaptive sandwich beam is optimally estimated to model the system for vibration control. In the composition of a three layered beam, the ER fluid layer is embedded between two constraining layers. Using finite element (FE) method, the governing equations of the composite viscoelastic beam are derived. The developed model is compared with the results found in the literature. In addition, for a fabricated ER sandwich beam, the ASTM E756 standard is employed to estimate the complex shear modulus of the viscoelastic layer in different electric fields. An optimization procedure is conducted based on particle swarm optimization (PSO). In this process, the rough estimation of complex shear modulus extracted by ASTM E756 is modified to correlate the results of the FE model and the experimental tests. The updated FE model is mapped into an appropriate form that can be used for control objectives. Finally, a semi-active sliding mode control is utilized to attenuate the vibration of the adaptive sandwich beam by tuning its electric field dependent characteristics.

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Section: Optimal Viscoelastic Layer Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal parameters estimation and vibration control of a viscoelastic adaptive sandwich beam incorporating an electrorheological fluid layer

Allahverdizadeh

Mahjoob

Nasrollahzadeh

et al. 2013

Journal of Vibration and Control

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“…A Voigt material may be represented in the time domain by its differential equation, (1) where G is the shear modulus, h the viscosity, g is the shear strain and t the shear stress. Putting, for harmonic excitation (2) the complex relation equivalent to Equation (1) may be written as (3) where (4) is the complex modulus [6,7].…”

Section: Linear Viscoelastic Modelmentioning

confidence: 99%

“…Most investigators have made tests in shear mode. Others used modal parameters derived from a vibrating beam with a core of ER fluid in order to characterize the latter [3,4]. This paper deals with shear mode.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Electrical Properties of an Electrorheological Fluid

Nilsson

Ohlson

2000

Journal of Intelligent Material Systems and Structures

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Adaptive structures contain parts whose properties may be tuned so as to suit some purpose. Certain fluids change viscosity when subjected to an electrical field. This paper concerns the behaviour of such an electrorheological fluid, ERF, which may be characterized as visco-plastic with some elasticity present. The stress response to a prescribed strain is studied in tests. Various models for describing the observed behaviour are analyzed. Results show that modelling the ERF as a Bingham fluid gives a rather close fit for low field strength. A solid mechanics model which displays yielding with kinematic strain hardening is preferred for high field strength as it then describes the observed amplitude and frequency dependence quite well. Relevant constants for investigated models are listed as functions of the field strength. The electrical behaviour is essential in designing parts for on-line response of structures, in order to control vibrations. Results show that a damper containing ERF responds to applied voltage as a capacitor whose leak resistance depends on voltage whereas its capacity does not. AC as well as DC fields are treated. When subjected to harmonic displacement the force response of the damper contains superharmonics owing to the non-linearity of the ERF. In AC powered dampers, intermodulation frequencies between field and displacement are identified.

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“…They observed that the application of an electric field increased both the frequency of the various resonance modes and the loss factor associated with each mode. Mahjoob et al [10] experimentally and theoretically studied composite beams filled with ER material under cantilever boundary conditions. They used a model to predict the mechanical properties of the composite beam, and developed a methodology to extract the complex modulus of the ER layer from modal parameters of the beam.…”

Section: Introductionmentioning

confidence: 99%

Free vibration and forced harmonic response of an electrorheological fluid-filled sandwich plate

Hasheminejad

Maleki

2009

Smart Mater. Struct.

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A dynamic model for the electric field-dependent steady-state vibrational response of a rectangular sandwich plate with a tunable electrorheological fluid (ERF) interlayer, subjected to a general harmonic transverse excitation, is developed. Hamilton's principle and the classical thin plate theory are applied to derive a set of fully coupled dynamic equations of motion along with the associated general boundary conditions. Assuming simply-supported edge conditions, the displacement components of the ERF-based sandwich plate are postulated by means of generalized double Fourier series with frequency-dependent coefficients. The natural frequencies and modal loss factors are subsequently determined by solving a complex eigenvalue problem. Analytical solutions are also obtained for the forced vibration characteristics of the adaptive structure under different external transverse excitations of varying frequency (0-300 Hz) and applied electric field strength (0-3.5 kV mm −1 ). Primary attention is focused on the effects of electric field magnitude, geometric aspect ratio, loading type, and ER core layer thickness on the dynamic characteristics of the sandwich plate. In addition, an effort is made to find the optimal electric field which yields minimized vibration amplitude for each excitation frequency. Limiting cases are considered and good agreements with the numerical solutions available in the literature are obtained.

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Identification of damping and stiffness of smart structures incorporating ER fluids

Cited by 14 publications

References 12 publications

Optimal parameters estimation and vibration control of a viscoelastic adaptive sandwich beam incorporating an electrorheological fluid layer

Optimal parameters estimation and vibration control of a viscoelastic adaptive sandwich beam incorporating an electrorheological fluid layer

Mechanical and Electrical Properties of an Electrorheological Fluid

Free vibration and forced harmonic response of an electrorheological fluid-filled sandwich plate

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