Vibration Response Analysis of MRE Cantilever Sandwich Beam under Non-Homogeneous Magnetic Fields

2013 ◽  
Vol 303-306 ◽  
pp. 49-52 ◽  
Author(s):  
Ming Long ◽  
Guo Liang Hu ◽  
Shao Long Wang
Keyword(s):  
Magnetic Fields ◽  
Natural Frequency ◽  
Vibration Isolation ◽  
Sandwich Beam ◽  
Rolling Stock ◽  
Transverse Motion ◽  
Response Analysis ◽  
Ansys Software ◽  
Motion Equations ◽  
Theoretical Results

A three layer sandwich beam with an aluminum face sheet and a magnetorheological elastomer (MRE) core was fabricated. The transverse motion equations of MRE cantilever sandwich beam under non-homogeneous magnetic fields were derived with the fine Mead-Markus model, and the first natural frequency of the beam were calculated. Meanwhile, the first natural frequency of the beam was also simulated using ANSYS software. The numerical simulations accorded with theoretical results in general. The results are expected to provide guidance to develop broadband vibration isolation devices for railways and rolling stock.

Stability and vibration analysis of an axially moving thin walled conical shell

2021 ◽  
pp. 107754632199760
Author(s):  
Hossein Abolhassanpour ◽  
Faramarz Ashenai Ghasemi ◽  
Majid Shahgholi ◽  
Arash Mohamadi
Keyword(s):  
Natural Frequency ◽  
Conical Shell ◽  
Shell Theory ◽  
Cone Angle ◽  
Theory Of Elasticity ◽  
Lower Velocity ◽  
Motion Equations ◽  
Conical Shells ◽  
Divergence Instability ◽  
Axially Moving

This article deals with the analysis of free vibration of an axially moving truncated conical shell. Based on the classical linear theory of elasticity, Donnell shell theory assumptions, Hamilton principle, and Galerkin method, the motion equations of axially moving truncated conical shells are derived. Then, the perturbation method is used to obtain the natural frequency of the system. One of the most important and controversial results in studies of axially moving structures is the velocity detection of critical points. Therefore, the effect of velocity on the creation of divergence instability is investigated. The other important goal in this study is to investigate the effect of the cone angle. As a novelty, our study found that increasing or decreasing the cone angle also affects the critical velocity of the structure in addition to changing the natural frequency, meaning that with increasing the cone angle, the instability occurs at a lower velocity. Also, the effect of other parameters such as aspect ratio and mechanical properties on the frequency and instability points is investigated.

The Finite Element Analysis and Optimization for the Grinder Based on the Joint Surface

2013 ◽  
Vol 281 ◽  
pp. 165-169 ◽  
Author(s):  
Xiang Lei Zhang ◽  
Bin Yao ◽  
Wen Chang Zhao ◽  
Ou Yang Kun ◽  
Bo Shi Yao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Joint Surface ◽  
Weak Links ◽  
Response Analysis ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Harmonic Response Analysis ◽  
Grinding Machine

Establish the finite element model for high precision grinding machine which takes joint surface into consideration and then carrys out the static and dynamic analysis of the grinder. After the static analysis, modal analysis and harmonic response analysis, the displacement deformation, stress, natural frequency and vibration mode could be found, which also helps find the weak links out. The improvement scheme which aims to increase the stiffness and precision of the whole machine has proposed to efficiently optimize the grinder. And the first natural frequency of the optimized grinder has increased by 68.19%.

Theoretical and Experimental Research of Viscoelastic Damping Limb-Like-Structure Device with Coupling Nonlinear Characteristics

2021 ◽  
pp. 2130002
Author(s):  
Zhen-Hua He ◽  
Zhao-Dong Xu ◽  
Jian-Yang Xue ◽  
Xing-Jian Jing ◽  
Yao-Rong Dong ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Harmonic Balance Method ◽  
Viscoelastic Damping ◽  
Static Stiffness ◽  
Viscoelastic Damper ◽  
Stiffness Analysis ◽  
Nonlinear Dynamic Equation ◽  
New Type ◽  
Geometrical Effects ◽  
Theoretical Results

The nonlinear characteristic of vibration control systems has attracted increasing attention for its advantage in improving structural performance. In this paper, a new type of viscoelastic damping limb-like-structure (VE-LLS) device is proposed by combing the viscoelastic (VE) damper and limb-like-structure (LLS) together, which possesses coupling nonlinearity characteristic caused by geometric and material factors, as well as a remarkable advantage in improving the control performance. First, to explore the nonlinear geometrical effects on the static stiffness of the VE-LLS device, a formula is derived from static stiffness, and the results are discussed. Second, dynamic analysis is performed of the proposed device considering the coupling geometrical and material nonlinearities in frequency domain, with the real-time effect of frequency and temperature on the mechanical properties of the viscoelastic damper considered in solving the nonlinear vibration equation. The harmonic balance method (HBM) is used to solve the nonlinear dynamic equation. Then, the displacement transmissibility of the VE-LLS device is calculated and assessed. The results indicate that the proposed device possesses excellent vibration isolation performance, and the geometric parameters of the viscoelastic damper have significant nonlinear effect on the performance. Finally, an experiment is carried out of the VE-LLS device to verify the accuracy of the static stiffness analysis. The results show that the theoretical results agree well the experimental ones, and that the theoretical results have high accuracy and reliability.

scholarly journals Damping of vertical and horizontal transverse vibrations in the bridge span structures

2018 ◽  
Vol 216 ◽  
pp. 01015
Author(s):  
Darya Provornaya ◽  
Sergey Glushkov ◽  
Leonid Solovyev
Keyword(s):  
High Speed ◽  
Vibration Isolation ◽  
Seismic Protection ◽  
Rolling Stock ◽  
Railway Bridge ◽  
Vibration Damper ◽  
Dynamic Vibration ◽  
Bridge Span ◽  
Transverse Vibrations ◽  
Dynamic Damping

The paper considers the issues of vibration isolation of railway bridge units on high-speed lines and seismic protection using dynamic vibration dampers. The purpose of the research is to justify the efficiency of damping the dynamic vibrations of the bridge supports with seismic insulating support parts. The research methodology involves building mathematical models of the systems under consideration and their numerical analysis. The methods of structural mechanics and dynamics of structures were used for solving the assigned tasks. The basic mathematical dependences of the vibration system with two seismic masses were developed. The rolling stock was represented by concentrated forces moving along the span structure. As a result, a new scheme for dynamic damping of vibration of the bridge supports was proposed according to which the span structure used as the dynamic vibration damper has an additional fastening on a rigid abutment.

Vibration Analysis of a Flexible System Mounted on a Viscoelastic Sandwich Beam

1982 ◽  
Vol 104 (2) ◽  
pp. 445-452
Author(s):  
R. C. Das Vikal ◽  
K. N. Gupta ◽  
B. C. Nakra
Keyword(s):  
Vibration Analysis ◽  
Sandwich Beam ◽  
Physical Parameters ◽  
Displacement Response ◽  
Flexible System ◽  
Viscoelastic Core ◽  
Theoretical Results

Vibration analysis of a simple flexible system mounted arbitrarily on a three-layer sandwich beam having a viscoelastic core and elastic faces is presented in this paper. The flexible system consists of a mass on rubber spring and is excited harmonically. The expressions for displacement response of mass and transmissibility provided by the whole system are obtained. The displacement response and transmissibility are studied for different geometrical and physical parameters of the sandwich beam. Some of the theoretical results are verified experimentally.

scholarly journals Ansys code applied to investigate the dynamics of composite sandwich beams

2021 ◽  
Vol 25 (1) ◽  
pp. 62-71
Author(s):  
Agnieszka Chudzik
Keyword(s):  
Sandwich Beam ◽  
Strength Properties ◽  
Effect Of Temperature ◽  
Material Strength ◽  
Beam Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Composite Sandwich ◽  
Viscoelastic Core ◽  
Influence Of Temperature On

Abstract A numerical analysis of the effect of temperature on the dynamics of the sandwich beam model with a viscoelastic core is presented. The beam under analysis was described with a standard rheological model. This solution allows one to study the effect of temperature on material strength properties. Calculations were performed with the Finite Element Method in the ANSYS software. The analysis of the results of the numerical calculations showed a significant influence of temperature on the strength properties of the model under test. The analysis confirmed damping properties of viscoelastic materials.

scholarly journals Design optimization of vehicle asynchronous motors based on fractional harmonic response analysis

2021 ◽  
Vol 12 (1) ◽  
pp. 689-700
Author(s):  
Ao Lei ◽  
Chuan-Xue Song ◽  
Yu-Long Lei ◽  
Yao Fu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Asynchronous Motor ◽  
Element Model ◽  
Design Parameters ◽  
Response Analysis ◽  
Harmonic Response ◽  
First Order ◽  
Harmonic Response Analysis

Abstract. To make vehicles more reliable and efficient, many researchers have tried to improve the rotor performance. Although certain achievements have been made, the previous finite element model did not reflect the historical process of the motor rotor well, and the rigidity and mass in rotor optimization are less discussed together. This paper firstly introduces fractional order into a finite element model to conduct the harmonic response analysis. Then, we propose an optimal design framework of a rotor. In the framework, objective functions of rigidity and mass are defined, and the relationship between high rigidity and the first-order frequency is discussed. In order to find the optimal values, an accelerated optimization method based on response surface (ARSO) is proposed to find the suitable design parameters of rigidity and mass. Because the higher rigidity can be transformed into the first-order natural frequency by objective function, this paper analyzes the first-order frequency and mass of a motor rotor in the experiment. The results proved that not only is the fractional model effective, but also the ARSO can optimize the rotor structure. The first-order natural frequency of asynchronous motor rotor is increased by 11.2 %, and the mass is reduced by 13.8 %, which can realize high stiffness and light mass of asynchronous motor rotors.

scholarly journals Баллистическое течение двумерных электронов в магнитном поле

2021 ◽  
Vol 55 (7) ◽  
pp. 566
Author(s):  
А.Н. Афанасьев ◽  
П.С. Алексеев ◽  
А.А. Грешнов ◽  
М.А. Семина
Keyword(s):  
Magnetic Fields ◽  
Ballistic Transport ◽  
Ballistic Regime ◽  
Electron Collisions ◽  
Viscosity Effect ◽  
Small Density ◽  
Longitudinal Resistance ◽  
Analytical Formulas ◽  
Sample Width ◽  
Theoretical Results

In conductors with a very small density of defects, electrons at low temperatures collide predominantly with a sample edges. Therefore, the ballistic regime of charge and heat transport is realized. The application of a perpendicular magnetic field substantially modifies the character of ballistic transport. For the case of two-dimensional (2D) electrons in the magnetic fields corresponding to the diameter of the cyclotron trajectories smaller than the sample width a hydrodynamic transport regime is formed. In the latter regime, the flow is mainly controlled by rare electron–electron collisions, which determine the viscosity effect. In this work, we study the ballistic flow of 2D electrons in long samples in magnetic fields up to the critical field of the transition to the hydrodynamic regime. From solution of the kinetic equation, we obtain analytical formulas for the profiles of the current density and the Hall electric field far and near the ballistic-hydrodynamic transition as well as for the longitudinal and Hall resistances in these ranges. Our theoretical results, apparently, describe the observed longitudinal resistance of pure graphene samples in the diapason of magnetic fields below the ballistic-hydrodynamic transition.

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