scholarly journals Bending Vibration Analysis of Nanobeams using the Nonlocal Motion Equations Solved by an Integral Approach

2021 ◽  
Vol 13 (1) ◽  
pp. 11-18
Author(s):  
Viorel ANGHEL ◽  
Stefan SOROHAN
Keyword(s):  
Vibration Analysis ◽  
Integral Method ◽  
Scale Effects ◽  
Integral Approach ◽  
Bending Vibrations ◽  
Bending Vibration ◽  
Motion Equations ◽  
Numerical Examples ◽  
Method Effects ◽  
Good Agreement

This paper deals with the dynamic characteristics for bending vibrations of Euler-Bernoulli type nanobeams taking into account the scale effects via the nonlocal motion equations. An integral method, based on the use of Green’s functions, has been used in order to obtain the corresponding eigenvalue problem. The proposed integral approach is an approximate matrix method. Effects of different boundary conditions and of an elastic foundation have been also included. The presented numerical examples show good agreement when compared to results from literature. The proposed method can be used in the case of nanodevices analysis modeled as beams (MEMS, NEMS).

scholarly journals Numerical Methods for Transverse Vibration Analysis of Straight Euler and Timoshenko Beams

2019 ◽  
Vol 11 (3) ◽  
pp. 15-28 ◽  
Author(s):  
Viorel ANGHEL
Keyword(s):  
Numerical Methods ◽  
Vibration Analysis ◽  
Integral Method ◽  
Short Review ◽  
Timoshenko Beams ◽  
Matrix Formulation ◽  
Inertia Effects ◽  
Approximate Integral ◽  
Shear Effects ◽  
Good Agreement

This paper presents a short review of numerical methods used for lateral vibration analysis in the case of straight Euler and Timoshenko beams. A particular integral method is described with more details. This approximate integral method is based on the use of flexibility influence functions (Green’s functions). It leads to a matrix formulation and to an eigenvalue problem for vibration analysis. The presented approach is able to estimate separately the shear effects and the rotary inertia effects and also the combined effects. Simple numerical examples are also presented for comparisons with analytical and finite elements results. The results show good agreement.

scholarly journals Integral Method for Flow Induced Transverse Vibrations Analysis of Flexible Pipes

2020 ◽  
Vol 12 (1) ◽  
pp. 3-11
Author(s):  
Viorel ANGHEL ◽  
Stefan SOROHAN
Keyword(s):  
Vibration Analysis ◽  
Integral Method ◽  
Free Vibration Analysis ◽  
Matrix Formulation ◽  
Beam Dynamic ◽  
Transverse Vibrations ◽  
Flexible Pipes ◽  
Fluid Velocities ◽  
Straight Beam ◽  
Good Agreement

This paper reviews some existing studies and numerical methods used for flow induced transverse vibrations analysis of flexible pipes. An integral method, based on the use of Green’s functions, already used for different straight beam dynamic analysis is adapted for the proposed subject. This approximate method leads to a matrix formulation and to an eigenvalue problem for free vibration analysis. The presented approach is able to estimate also the critical fluid velocities. Effects of boundary conditions and of elastic foundation characteristics, Coriolis terms and of other parameters on dynamic behavior of a pipe, can be included. Some numerical examples are also presented for comparisons with results obtained by FEM or with other data from literature. They show good agreement.

scholarly journals Design and Performance Evaluation of a Single-Phase Driven Ultrasonic Motor Using Bending-Bending Vibrations

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 853
Author(s):  
Dongmei Xu ◽  
Wenzhong Yang ◽  
Xuhui Zhang ◽  
Simiao Yu
Keyword(s):  
Single Phase ◽  
Oblique Line ◽  
Ultrasonic Motor ◽  
Vibration Modes ◽  
Bending Vibrations ◽  
Bending Vibration ◽  
Output Performance ◽  
Resonance Frequencies ◽  
And Performance ◽  
Line Trajectory

An ultrasonic motor as a kind of smart material drive actuator has potential in robots, aerocraft, medical operations, etc. The size of the ultrasonic motor and complex circuit limits the further application of ultrasonic motors. In this paper, a single-phase driven ultrasonic motor using Bending-Bending vibrations is proposed, which has advantages in structure miniaturization and circuit simplification. Hybrid bending vibration modes were used, which were excited by only single-phase voltage. The working principle based on an oblique line trajectory is illustrated. The working bending vibration modes and resonance frequencies of the bending vibration modes were calculated by the finite element method to verify the feasibility of the proposed ultrasonic motor. Additionally, the output performance was evaluated by experiment. This paper provides a single-phase driven ultrasonic motor using Bending-Bending vibrations, which has advantages in structure miniaturization and circuit simplification.

Evaluation of Motorized Rotating Pancake Coil Probe Signals Simulated by Numerical Analysis in Steam Generator Tubes

2006 ◽  
Vol 321-323 ◽  
pp. 451-454
Author(s):  
Joo Young Yoo ◽  
Sung Jin Song ◽  
Chang Hwan Kim ◽  
Hee Jun Jung ◽  
Young Hwan Choi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Steam Generator ◽  
Integral Method ◽  
Volume Integral ◽  
Analysis Software ◽  
Steam Generator Tubes ◽  
Calibration Tool ◽  
High Possibility ◽  
Good Agreement

In the present study, the synthetic signals from the combo tube are simulated by using commercial electromagnetic numerical analysis software which has been developed based on a volume integral method. A comparison of the simulated signals to the experiments is made for the verification of accuracy, and then evaluation of five deliberated single circumferential indication signals is performed to explore a possibility of using a numerical simulation as a practical calibration tool. The good agreement between the evaluation results for two cases (calibration done by experiments and calibration made by simulation) demonstrates such a high possibility.

Theoretical Assessment of Compressibility Factor of Gases by Using Second Virial Coefficient

2018 ◽  
Vol 73 (2) ◽  
pp. 121-125
Author(s):  
Bahtiyar A. Mamedov ◽  
Elif Somuncu ◽  
Iskender M. Askerov
Keyword(s):  
Virial Coefficient ◽  
Second Virial Coefficient ◽  
Compressibility Factor ◽  
Analytical Approximation ◽  
Accurate Evaluation ◽  
Numerical Examples ◽  
Lennard Jones ◽  
Theoretical Assessment ◽  
Good Agreement

AbstractWe present a new analytical approximation for determining the compressibility factor of real gases at various temperature values. This algorithm is suitable for the accurate evaluation of the compressibility factor using the second virial coefficient with a Lennard–Jones (12-6) potential. Numerical examples are presented for the gases H2, N2, He, CO2, CH4 and air, and the results are compared with other studies in the literature. Our results showed good agreement with the data in the literature. The consistency of the results demonstrates the effectiveness of our analytical approximation for real gases.

Flapwise Bending Vibration Analysis of Rotating Tapered Rayleigh Beams for the Application of Offshore Wind Turbine Blades

2021 ◽  
Vol 35 (4) ◽  
pp. 544-553
Author(s):  
Yan-fei Chen ◽  
Zhi-peng Zang ◽  
Shao-hua Dong ◽  
Chuan Ao ◽  
Hao Liu ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vibration Analysis ◽  
Turbine Blades ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Turbine Blades ◽  
Bending Vibration

Influence of Interaction Between Torsion and Bending on Long-Term Nonlinear Rotor Dynamics

1999 ◽  
Author(s):  
Jiazhong Zhang ◽  
Bram de Kraker ◽  
Dick H. van Campen
Keyword(s):  
Critical Speed ◽  
Floquet Theory ◽  
Rotor Dynamics ◽  
Steady State Response ◽  
Bending Vibrations ◽  
Bending Vibration ◽  
State Response ◽  
Stability And Bifurcation ◽  
The Stability

Abstract An elementary system with gears and excited by unbalance mass has been constructed for analyzing the interaction between torsion and bending vibration in rotor dynamics. For this system, only the interaction caused primarily by unbalance mass has been investigated. The stability and bifurcation characteristics of the system have been studied by numerical computation based on Hopf bifurcation and Floquet theory. The results show that the interaction between torsion and bending vibrations can affect the stability and bifurcation of the unbalance response, in particular the onset speed of instability. In addition to the above, the interaction also affects the steady-state response. To investigate the influence of unbalance mass, the periodic solution and its stability have been studied near the first bending critical speed of the decoupled system. All the results show that the coupling of torsion and bending vibrations can have a significant influence on the nonlinear dynamics of the whole system.

scholarly journals Nonlinear Vibration Analysis of Rotor considering Cogging and Harmonic Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shanle Li ◽  
Feng Liu ◽  
Hongyan Wang ◽  
Haijun Song ◽  
Kuilong Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Magnetic Force ◽  
Rotor System ◽  
Kutta Method ◽  
Rotor Vibration ◽  
Motion Equations ◽  
Runge Kutta Method ◽  
Static Eccentricity ◽  
New Formula

This paper aims to investigate nonlinear vibration characteristics of rotor system considering cogging and harmonic effects. Firstly, relative permeance with eccentric was established and then corrected by correction factor caused by the cogging effect. Based on the new formula of relative permeance, the expression of unbalanced magnetic force was obtained, and the coefficient of cogging effect was defined. Motion equations of rotor system were established, and Runge–Kutta method was used to solve the equations. Results showed that errors between finite and analytical results were smaller considering cogging and harmonic effects. When the harmonics were taken into consideration, the vibration of rotor increases sharply. When the cogging and harmonics were taken into consideration simultaneously, the vibration of rotor decreased instead, which means that stator slots have the effect of reducing vibration in rotor system. Rotor vibration was axis symmetry with static eccentricity rather than central symmetry with no eccentricity, and double, four times, and six times supply frequency always existed in the components of main frequency with eccentric.

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