Hybrid stiff-string–polynomial basis functions for vibration analysis of high speed rotating beams

2009 ◽  
Vol 87 (3-4) ◽  
pp. 254-265 ◽  
Author(s):  
Jagadish Babu Gunda ◽  
R.K. Gupta ◽  
Ranjan Ganguli
Keyword(s):  
Vibration Analysis ◽  
High Speed ◽  
Basis Functions ◽  
Polynomial Basis ◽  
Rotating Beams

Stiff-String Basis Functions for Vibration Analysis of High Speed Rotating Beams

2008 ◽  
Vol 75 (2) ◽  
Author(s):  
Jagadish Babu Gunda ◽  
Ranjan Ganguli
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Natural Frequencies ◽  
Basis Functions ◽  
Beam Equation ◽  
Rotating Beam ◽  
Rotating Beams ◽  
Centrifugal Stiffening ◽  
Convergence Study ◽  
Stiffening Effect

A new rotating beam finite element is developed in which the basis functions are obtained by the exact solution of the governing static homogenous differential equation of a stiff string, which results from an approximation in the rotating beam equation. These shape functions depend on rotation speed and element position along the beam and account for the centrifugal stiffening effect. Using this new element and the Hermite cubic finite element, a convergence study of natural frequencies is performed, and it is found that the new element converges much more rapidly than the conventional Hermite cubic element for the first two modes at higher rotation speeds. The new element is also applied for uniform and tapered rotating beams to determine the natural frequencies, and the results compare very well with the published results given in the literature.

The Use of Modan 3D in Experimental Modal Analysis

2013 ◽  
Vol 486 ◽  
pp. 36-41 ◽  
Author(s):  
Róbert Huňady ◽  
František Trebuňa ◽  
Martin Hagara ◽  
Martin Schrötter
Keyword(s):  
Modal Analysis ◽  
Vibration Analysis ◽  
High Speed ◽  
Mechanical Vibration ◽  
Steel Sample ◽  
Experimental Modal Analysis ◽  
Image Correlation ◽  
Optical Methods ◽  
Mode Shapes ◽  
Vibration Modes

Experimental modal analysis is a relatively young part of dynamics, which deals with the vibration modes identification of machines or their parts. Its development has started since the beginning of the eighties, when the computers hardware equipment has improved and the fast Fourier transform (FFT) could be used for the results determination. Nowadays it provides an uncountable set of vibration analysis possibilities starting with conventional contact transducers of acceleration and ending with modern noncontact optical methods. In this contribution we mention the use of high-speed digital image correlation by experimental determination of mode shapes and modal frequencies. The aim of our work is to create a program application called Modan 3D enabling the performing of experimental modal analysis and operational modal analysis. In this paper the experimental modal analysis of a thin steel sample performed with Q-450 Dantec Dynamics is described. In Modan 3D the experiment data were processed and the vibration modes were determined. The reached results were verified by PULSE modulus specialized for mechanical vibration analysis.

Random Vibration Analysis of the Underframe Structure on a High-Speed Train

ICTE 2015 ◽  
2015 ◽  
Author(s):  
Hanfei Guo ◽  
Xiaoxue Liu ◽  
Wei Tong ◽  
Youwei Zhang ◽  
Yanlei Zhang
Keyword(s):  
Vibration Analysis ◽  
High Speed ◽  
Random Vibration ◽  
High Speed Train ◽  
Random Vibration Analysis

A Study on the Method of Vibration Analysis for Korean High Speed Train by the On-Line Test

2006 ◽  
Vol 321-323 ◽  
pp. 1593-1596 ◽  
Author(s):  
Chan Kyoung Park ◽  
Ki Whan Kim ◽  
Jin Yong Mok ◽  
Young Guk Kim ◽  
Seog Won Kim
Keyword(s):  
Vibration Analysis ◽  
High Speed ◽  
Vibration Mode ◽  
Dynamic Performance ◽  
Railway Vehicle ◽  
High Speed Train ◽  
Acceleration Data ◽  
On Line ◽  
System Vibration ◽  
Line Test

The Korean High Speed Train (KHST) has been tested on the Kyongbu high speed line and the Honam conventional line since 2002. A data acquisition system was developed to test and prove the dynamic performance of the KHST, and the system has been found to be very efficient in acquiring multi-channel data from accelerometers located all over the train. Also presented in this paper is an analysis procedure which is simple and efficient in analyzing the acceleration data acquired during the on-line test of the KHST. The understanding of system vibration mode for a railway vehicle is essential to evaluate the characteristics of a dynamic system and to diagnose the dynamic problems of the vehicle system during tests and operations. Methods based on homogeneous linear systems are not realistic because real systems have nonlinear characteristics and are strongly dependent on environmental conditions. In this paper an efficient method of vibration analysis has been proposed and applied for the KHST to evaluate its vibration mode characteristics. The results show that this method is suitable to estimate the system vibration modes of the KHST.

The Surface Variational Principle: A Different Perspective for Structural Acoustic Modeling

1997 ◽  
Author(s):  
J. H. Ginsberg
Keyword(s):  
Fourier Series ◽  
Variational Principle ◽  
Vibration Analysis ◽  
Basis Functions ◽  
Acoustic Modeling ◽  
Normal Velocity ◽  
Convergence Properties ◽  
Variational Functional ◽  
Acoustic Interaction ◽  
System Equations

Abstract This paper surveys the development and application of the surface variational principle (SVP) governing the acoustic interaction between surface pressure and normal velocity. SVP is analogous to the method of assumed modes for vibration analysis, in that it represents the response in terms of a sequence of basis functions that are globally defined. The system equations governing the series coefficients are obtained by requiring that the value of the variational functional be stationary. In the wavenumber-based version of SVP, the pressure and velocity are represented by dual range Fourier series. A brief description of the steps entailed in formulating the SVP equations and coupling them to the equations for an elastic structure is provided. Then the computational requirements of an SVP analysis relative to conventional boundary element and finite element techniques are discussed. This is followed by an example illustrating the convergence properties of SVP. Another example is used to highlight the physical interpretation of the SVP representation of surface response. The evolution of the present version of SVP is surveyed, along with some of its applications. The paper closes with a brief discussion of possible future applications of the method.

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