نتایج جستجو برای: viscoelastic damping
تعداد نتایج: 34682 فیلتر نتایج به سال:
Motivated by a desire to engineer stiff materials (e.g., ceramics) to also have high energy dissipation, the viscoelastic stiffness and damping in ferroelectric ceramics subjected to electric fi elds higher than the coercive fi eld is investigated. Indeed, dynamic excitations of ferroelectrics occur in many of their applications, e.g., in sensors and actuators; thus, there is interest in studyi...
A Combined Honeycomb and Solid Viscoelastic Material for Structural Damping Applications (2001-2002)
The goal of the research described in this paper is to investigate the feasibility of a new combined polymer composite damping system, which consists of a polymer honeycomb material and a viscoelastic solid material. This new combined viscoelastic system, which is intended primarily for energy dissipation and vibration control, serves as an interface layer within lightweight composite panels su...
Dynamic viscoelastic properties of bamboo were determined in torsion and bending. Damping, measured by tan δ, in dry bamboo was relatively small, about 0.01 in bending and 0.02 to 0.03 in torsion, with little dependence on frequency in the audio range. In wet bamboo, damping was somewhat greater: 0.012 to 0.015 in bending and 0.03 to 0.04 in torsion. The anisotropy in damping implies a purely c...
The small-amplitude radial oscillations of a gas microbubble encapsulated by a viscoelastic solid shell and surrounded by a slightly compressible viscoelastic liquid are studied theoretically. The Kelvin–Voigt and 4-constant Oldroyd models are used to describe the viscoelastic properties of the shell and liquid, respectively. The equation for radial oscillation is derived using the method of ma...
Many instruments used to measure viscoelastic properties are only capable of subjecting a sample to a limited range of loading frequencies. For thermorheologically simple materials, it is assumed that a change in temperature is equivalent to a shift of the viscoelastic behavior on the log frequency or time axis. For many materials, time–temperature superposition appears to work well for modulus...
This paper describes the development of an efficient finite element model for dynamic analysis of laminated beams treated by a constrained viscoelastic layer. The finite element model is designed so as to represent the viscoelastic core shear accurately. An offset-beam element which takes shear deformation into account and is specially suited for modeling such laminated beams is developed. The ...
The nonlinear vibration analysis of a directly excited cantilever beam modeled as an inextensible viscoelastic Euler–Bernoulli beam has been studied by the authors and is reported in the literature. The viscoelastic damping was modeled as Kelvin–Voigt damping, and the nonlinearities arisen from the inextensibility assumption. This paper extends our theoretical developments presented in the prev...
We present a method to improve accuracy in measurements of nanoscale viscoelastic material properties with contact resonance atomic force microscope methods. Through the use of the two-dimensional hydrodynamic function, we obtain a more precise estimate of the fluid damping experienced by the cantilever-sample system in contact resonance experiments, leading to more accurate values for the tip-...
In this paper, natural frequencies and dynamic response of thick beams made of saturated porous materials resting on viscoelastic foundation are investigated for the first time. The beam is modeled using higher-order beam theory. Kelvin-voight model is used to model the viscoelastic foundation. Distribution of porosity along the thickness is considered in two different patterns, which are symme...
In this paper, we present an analytical method for solving a well-posed boundary value problem of mathematical physics governing the vibration characteristics of an internal flow propelled fluid-structure interaction where the pipeline segment is idealized as an elastic hollow beam conveying an incompressible fluid on a viscoelastic foundation. The effect of Coriolis and damping forces on the o...
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