The effect of visco-elastic core thickness on modal loss factors of a thick three-layer cylinder

Abstract

Free vibrations of damped three-layer sandwich cylinders with thick layers are considered. In particular, the effect of the different thicknesses for the middle layer on the overall natural frequencies and modal damping factors are studied. The constrained-layer damping is accomplished by sandwiching a linear visco-elastic material between two isotropic elastic cylinders with the same properties. The governing equations are derived analytically by applying Newton's second law of motion for a three-dimensional elastic medium, and by employing complex elastic moduli for the sandwiched layer. Dimensionless natural frequencies and modal loss factors for the first three thickness modes associated with wave numbers of n = 0, 1, 2, 3, and 4 are tabulated for a range of thicknesses for the middle visco-elastic layer while keeping the thicknesses of inner and outer layers unchanged.

Keywords

free vibrations of cylinders thick-layered sandwich cylinders modal analysis modal loss factors damping treatment constrained-layer damping visco-elastic

Get full access to this article

View all access options for this article.

References

Leissa

A. W.

‘Vibration of shells’ (1973): NASA SP - 288

Markus

The mechanics of vibrations of cylindrical shells (New York: Elsevier 1988)

Hamidzadeh

H. R.

Medhora

A. A.

‘Free transverse vibrations of composite shells with discontinuous constraining layers’ (1995)

Y. Y.

‘Vibrations of elastic sandwich cylindrical shells’

J. Appl. Mech. 27 (1960): 653–662

Y. P.

Douglas

B. E.

Thomas

E. V.

‘Mechanical impedance of deamped three-layered sandwich rings’

AIAA J. 113 (1973): 300–304

Y. P.

Everstine

G. C.

‘More on finite element modeling of damped composite systems’

J. Sound Vibr. 692 (1980): 199–205

Hamidzadeh

H. R.

Sawaya

N. N.

‘Free vibration of thick multi-layer cylinders’

J. Shock Vibr. 25 (1995): 393–401

Hamidzadeh

H. R.

Jiang

Modal loss-factors of thick three-layer cylinders with visco-elastic core

In Proceedings of the ASME Design Engineering Technical Conference, 1995, vol. 3, part C, pp. 3–8. part C

Armenakas

A. E.

‘Propagation of harmonic waves in composite circular cylindrical shells, part 1: Theoretical investigation’

AIAA J. 5 (1967): 740–744

10.

Armenakas

A. E.

‘Propagation of harmonic waves in composite circular cylindrical shells, part 2: Numerical results’

AIAA J. 9 (1971): 599–605

11.

Armenakas

A. E.

Gazis

D. C.

Hermann

Free vibrations of circular cylindrical shells (Oxford: Pergamon Press 1969)

12.

Watson

G. N.

A treatise on the theory of Bessel functions (New York, USA: Cambridge University Press 1995)