6926475980

Hokkaido Univ.. Sapporo. 060 Japan, J. Acoust. Soc. Amer., 75 (4). pp 1118-1123 (Apr 1984) 7 figs. 1 table, 9 refs

Key Words: Shell*. Cylindrical *hell», Natural frequencies

An analyiis i* presented for the free vibration of an elastically or ragldly point-iupported circular cylindrical shell. For thit purpote. the deflection di*>lacement* of the shell are written in a teries of deflection function* of the beam. The dynami* cal enargłes of the shell are evaluated, and the frequency equation is derived by the Rłtz method. For a rigidly point* supportad shell, the Lagrangian multiplier method i* eon yeniently employed. The method is applied to a cylindrical shell supportad at symmetrically located four points, the natural frequencies and the modę shapes are calculated numerically, and the effects of the point supports on the yibration are studied.

The natural frequencies of a three-iayered elastic ring on periodic radial supports are obtained by using a wave ap-proach. Two types of support conditions are inyestigated. When the core is assumed to be viscoełastic, the theory of forced damped nor mai modes is usad to obtain the resonance frequencies and the associated composćte model los* factors of the damped itructure. The numericel results show the effects of the thickness ratios and the core shear modulus. The high values of the loss factor in some modes are ex-plained with the aid of the modę shapes of the corresponding elastic ring.

PIPES AND TUBES

(AIsoseeNo. 1827)

RINGS

84-1743

FlexuraJ Yibration of a Thin Rotating Ring

M. Endo. K. Hatamura, M. Sakata, and 0. Taniguchi Tokyo Inst. of Tech., Ookayama, Meguro-ku, Tokyo, Japan. J. Sound Vib..^2 (2). pp 261-272 (Jan 22. 1984) 7 figs, 2 tabJes, 15 refs

Key Words: Ring*, Rotating structures. Flexural vibration

•

Ftexural yibration of a thin rotating ring is irwestigated experknentally and theoretically. The frequenciesof forward and beckward flexural traveling waves are measured u ling strain geges. The ranga of rotationol speeds of the ring ind u des frequencies oompe rabie with that of the funda-mental flexural moda of a no nr o ta t i ng ring and the ttability of flexural yibration is examined with consideration of the effects of the centrifugal and Coriolis forces.

84-1745

CorreUtion of Support Impact Force and Fretting-Wear for a Heat Exchanger Tubę

P.L. Ko and H. Basista

Chalk River Nuclear Labs., Atomie Energy of Canada, Ltd., Chalk River, Ontario. Canada. J. Pressure Vessel Tech., Trans. ASME. 106 (1), pp 69-77 (Feb 1984) 12 figs. 2 tables. 8 refs

Key Words: Interaction: structure-support. Heat exchengers. Tubes, Fhitd-induceó excitatk>n

Flow-induced tuba yibration cen causa dynamie interactions between a tubę and its supports. Both weer information and results from yibration anelyses are needed to achieve a roalittic assessment of long-term tubę weer. Nor mai and oblique impact forces at the tubę supports characterize dynamie interaction between tubę and tubę-support, and can be correlated to the ratę of fretting-wear. A statistical analy* sis of the force signal provides an indication of the time distribution of various force levels during a yibration cycle. Different schemes for obtainirtg a weighted sum of these force levels were developed to account for changes in excita* tion levels, tube/support cleerance, and the type of tubę motion.

84-1744

Yibratsoa of i Three-Layered Ring on Periodic Radial Supports

E S. Reddy and A.K. Mallik

Indian Inst. of Tech., Kanpur, India, AIAA J.. 22 (4). pp 543-551 (Apr 1984) 10 figs, 17 refs

Key Words: Rings, Layered materiał*, Damped structures. Elastic core<ontalning media, Viscoelastic core-containing media, Supports, Boundary condition effects

84-1746

Reaponse of Multipaas Heat Exchangera to Sinusoidal Flow Ratę Giangea of Large Amplitudę

I. Todo

Yokohama Natl. Univ.. 165, Tokiwadai. Hodogaya-ku. Yokohama 240, Japan, Buli. JSME.J£7 (223), pp 87-94 (Jan 1984) 8 figs. 5 refs