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Structural Engineering and Mechanics Volume 44, Number 4, November25 2012, pages 521-538 DOI: http://dx.doi.org/10.12989/sem.2012.44.4.521 |
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Vibrations of an axially accelerating, multiple supported
flexible beam | ||
S. Kural and E. Ozkaya
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| Abstract [Full Text] | ||
| In this study, the transverse vibrations of an axially moving flexible beams resting on multiple supports are investigated. The time-dependent velocity is assumed to vary harmonically about a constant mean velocity. Simple-simple, fixed-fixed, simple-simple-simple and fixed-simple-fixed boundary conditions are considered. The equation of motion becomes independent from geometry and material properties and boundary conditions, since equation is expressed in terms of dimensionless quantities. Then the equation is obtained by assuming small flexural rigidity. For this case, the fourth order spatial derivative multiplies a small parameter; the mathematical model converts to a boundary layer type of problem. Perturbation techniques (The Method of Multiple Scales and The Method of Matched Asymptotic Expansions) are applied to the equation of motion to obtain approximate analytical solutions. Outer expansion solution is obtained by using MMS (The Method of Multiple Scales) and it is observed that this solution does not satisfy the boundary conditions for moment and incline. In order to eliminate this problem, inner solutions are obtained by employing a second expansion near the both ends of the flexible beam. Then the outer and the inner expansion solutions are combined to obtain composite solution which approximately satisfying all the boundary conditions. Effects of axial speed and flexural rigidity on first and second natural frequency of system are investigated. And obtained results are compared with older studies. | ||
| Key Words | ||
| beam vibrations; supported end; flexible beam; multiple supports; axially accelerating; small flexural stiffness; transverse vibrations | ||
| Address | ||
| S. Kural and E. Ozkaya: Department of Mechanical Engineering, Celal Bayar University, 45140 Muradiye, Manisa, Turkey | ||