Large Amplitude Free Vibration of Nanobeams Subjected to Magnetic Field Based on Nonlocal Elasticity Theory

2015 ◽  
Vol 764-765 ◽  
pp. 1199-1203 ◽  
Author(s):  
Tai Ping Chang
Keyword(s):  
Magnetic Field ◽  
Free Vibration ◽  
Nonlocal Elasticity ◽  
Beam Theory ◽  
Nonlinear Frequency ◽  
Bernoulli Beam ◽  
Nonlinear Free Vibration ◽  
Vibration Behavior ◽  
Bernoulli Beam Theory ◽  
Euler Bernoulli Beam

In the present study, nonlinear free vibration behavior of nanobeam subjected to magnetic field is investigated based on Eringen's nonlocal elasticity and Euler–Bernoulli beam theory. The Hamilton's principle is adopted to derive the governing equations together with Euler–Bernoulli beam theory and the von-Kármán's nonlinear strain–displacement relationships. An approximate analytical solution is obtained for the nonlinear frequency of the nanobeam under magnetic field by using the Galerkin method and He's variational method. In the numerical results, the ratio of nonlinear frequency to linear frequency is presented. The effect of nonlocal parameter on the nonlinear frequency ratio is studied; furthermore, the effect of magnetic field on the nonlinear free vibration behavior of nanobeam is investigated.

scholarly journals Free Vibration Analysis of DWCNTs Using CDM and Rayleigh-Schmidt Based on Nonlocal Euler-Bernoulli Beam Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Maria Anna De Rosa ◽  
Maria Lippiello
Keyword(s):  
Carbon Nanotubes ◽  
Free Vibration ◽  
Van Der Waals ◽  
Beam Theory ◽  
Van Der Waals Forces ◽  
Bernoulli Beam ◽  
Bernoulli Beam Theory ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Euler Bernoulli Beam

The free vibration response of double-walled carbon nanotubes (DWCNTs) is investigated. The DWCNTs are modelled as two beams, interacting between them through the van der Waals forces, and the nonlocal Euler-Bernoulli beam theory is used. The governing equations of motion are derived using a variational approach and the free frequencies of vibrations are obtained employing two different approaches. In the first method, the two double-walled carbon nanotubes are discretized by means of the so-called “cell discretization method” (CDM) in which each nanotube is reduced to a set of rigid bars linked together by elastic cells. The resulting discrete system takes into account nonlocal effects, constraint elasticities, and the van der Waals forces. The second proposed approach, belonging to the semianalytical methods, is an optimized version of the classical Rayleigh quotient, as proposed originally by Schmidt. The resulting conditions are solved numerically. Numerical examples end the paper, in which the two approaches give lower-upper bounds to the true values, and some comparisons with existing results are offered. Comparisons of the present numerical results with those from the open literature show an excellent agreement.

Application of homotopy perturbation method for dynamic analysis of nanotubes delivering nanoparticles

2020 ◽  
pp. 107754632093347
Author(s):  
Beytollah Rezapour ◽  
Mohammad Ali Fariborzi Araghi ◽  
Hector Vázquez-Leal
Keyword(s):  
Perturbation Method ◽  
Homotopy Perturbation Method ◽  
Order Approximation ◽  
Beam Theory ◽  
Nonlinear Frequency ◽  
Inertial Forces ◽  
Homotopy Perturbation ◽  
Vibration Behavior ◽  
Wide Range ◽  
Euler Bernoulli Beam

Because of the importance of the analytical study of the vibration behavior of nanotubes delivering nanoparticles, in this study, the transverse vibration of these systems has been studied by analytical approach based on the homotopy perturbation method. The nonlocal Euler–Bernoulli beam theory is used for derivation of the equation of motion. The interaction between nanoparticle and the inner wall of nanotube has been modeled by using van der Waals forces and considering the effects of inertial forces caused by centrifugal and Coriolis acceleration components of nanoparticles. After evaluation of the implemented analytical method by numerical results, it is revealed that the obtained second-order approximation response gives high accurate vibration behavior of these systems for a wide range of parameters. As well, these results show that inertial forces caused by motion of nanoparticle increase vibration amplitude of nanotube and change nonlinear frequency of the system.

Analysis of bimorph piezoelectric beam energy harvesters using Timoshenko and Euler–Bernoulli beam theory

2012 ◽  
Vol 24 (2) ◽  
pp. 226-239 ◽  
Author(s):  
Gang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Slenderness Ratio ◽  
Beam Theory ◽  
Bernoulli Beam ◽  
Energy Harvesters ◽  
Bernoulli Beam Theory ◽  
Spectral Finite Element ◽  
Euler Bernoulli Beam ◽  
Element Method

Single-degree-of-freedom lumped parameter model, conventional finite element method, and distributed parameter model have been developed to design, analyze, and predict the performance of piezoelectric energy harvesters with reasonable accuracy. In this article, a spectral finite element method for bimorph piezoelectric beam energy harvesters is developed based on the Timoshenko beam theory and the Euler–Bernoulli beam theory. Linear piezoelectric constitutive and linear elastic stress/strain models are assumed. Both beam theories are considered in order to examine the validation and applicability of each beam theory for a range of harvester sizes. Using spectral finite element method, a minimum number of elements is required because accurate shape functions are derived using the coupled electromechanical governing equations. Numerical simulations are conducted and validated using existing experimental data from the literature. In addition, parametric studies are carried out to predict the performance of a range of harvester sizes using each beam theory. It is concluded that the Euler–Bernoulli beam theory is sufficient enough to predict the performance of slender piezoelectric beams (slenderness ratio > 20, that is, length over thickness ratio > 20). In contrast, the Timoshenko beam theory, including the effects of shear deformation and rotary inertia, must be used for short piezoelectric beams (slenderness ratio < 5).

Case Study of the Effect of Combined Axial and Lateral Loadings on the Critical Buckling Capacity of Piping Supports

2020 ◽  
Author(s):  
Phillip Wiseman ◽  
Alex Mayes ◽  
Shreeya Karnik
Keyword(s):  
Large Deformation ◽  
Axial Loading ◽  
Beam Theory ◽  
Second Order ◽  
Lateral Acceleration ◽  
Bernoulli Beam ◽  
Deformation Method ◽  
Closed Form Solutions ◽  
Bernoulli Beam Theory ◽  
Euler Bernoulli Beam

Abstract Snubbers are used in industry to restrain piping in dynamic events which can see significant axial loading as well as lateral acceleration. Snubbers are often employed with an extension when required to bridge gaps between the piping and building structure. As a result, they are susceptible to buckling instability issues. The pipe support and restraint design by analysis buckling criteria for supports given within the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NF is investigated to determine the behavior of snubber assemblies under combined axial and lateral loadings. Four types of analyses are performed on the assemblies under the action of axial loading to demonstrate finite element and closed form solutions. These include the following: linear Eigen buckling, nonlinear second order large deformation method, energy method and Euler Bernoulli beam theory. In addition, a variety of snubber assembly sizes are subjected to combined axial and lateral loading in the form of multiple magnitudes of lateral acceleration. The behavior was analyzed by the Euler Bernoulli beam theory and nonlinear second order large deformation method. The techniques of each method are compared providing explanations of the assumptions taken, relevant limitations and recommended applications.

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