Three-dimensional elasticity solution for vibro-acoustic behavior of cylinder in the presence of subsonic flow

Document Type : Research Paper

Authors

1 Ph.D. Student, Mechanical Engineering Department, Iran University of Science & Technology

2 M.Sc.Student, School of Advanced Technologies, Iran University of Science & Technology

3 Professor, Mechanical Engineering Department, Iran University of Science & Technology

4 Associate Professor, Mechanical Engineering Department, Iran University of Science & Technology

Abstract

In this paper, the Three-dimensional (3-D) theory of elasticity has been used for sound transmission loss (TL) of a thin-walled cylindrical shell with infinite length. This structure is excited by an obliquely plane wave. Governing equations of the thin shell have been derived in radial, axial, and circumferential directions. Then, Helmholtz decomposition is applied to solve the equations. Therefore, the displacement field is considered in terms of Lame potential functions This method describes the vibrational behavior of the shells more accurately than other theories, including the classical theory and the first and third order of shear, due to the consideration of the effects of rotation and shear. A comparison of the present method results with those obtained from classical shell theory (CST) indicates an excellent agreement. However, at the high frequencies the classical encounter insufficient accuracies as a result of increasing the rotational terms as well as shear wave effects. The results show that with increasing shell thickness, due to increased flexural stiffness of the shell, the sound transmission loss has increased. By increasing the Mach number, due to the negative stiffness, reduces the sound transmission loss in the stiffness-controlled region and conversely increases the sound transmission loss in the mass-controlled region due to damping in the structure. Finally, it is shown that the critical and coincidence frequencies increase with the growing up Mach number.

Keywords

References

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Aerospace Knowledge and Technology Journal
Volume 9, Issue 2 - Serial Number 2
October 2020
Pages 243-254

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