6926475978

84-1738

Yibration and Subility of Orthotropie CircuUr Cylindricai Shells Subjected to Axial Load

G. Yamada. T. Irie, and M. Tsushima Hokkaido Univ., Sapporo. 060 Japan, J. Acoust. Soc. Amer., 75 (3). pp 842-848 (Mar 1984) 4 figs. 4 tables. 25 refs

Key Words: Shells, Cylindricai shells. Axial excrtatk>n, Trans-fer matrix method, Natural frequencies, Critical toad*

An analysis is presented for tha vibration and stability of an orthotropic circular cylindricai shell lobjactad to an axial static load by uae of the transfer matrix approach. The applicsbility of the thin-shell theory is assumed, and the governing equatk>ns of free vibration of the shell ara written in a matrix differential equation by using the transfer matrix of the shell. Once the matrix has been determined by a solu-tion to the equetk>n, the natural frequencies and the critical loads are calculated numerically in terms of the elements of the matrix for a given set of boundary conditions at the edges. This method isepplied to orthotropic circular cylindri-cal shells simply supported at the edges. and the effects of the łength ratio, orthotropy, and axial load on the vibration and stability are studied.

J.V. Kouri

School of Engrg., Air Force Inst. of Tech., Wright-Patterson AFB. OH. Rept. No. AFIT/GAE/AA/83-D-11,93 pp (Dec 1983)

AD-A136 901

Key Words: Shells, Cylindricai shells, Cantilever shells, Vari-ational methods, Natural frequencies. Modę thapes

This report develops a variational technique for the analysis of the vibratk>n characteristics of an open cylindricai canti-levered shell. The technique is devetoped by modifying Reissner*s principia, which normally appiies to static prob-lems, through the use of Hamilton’s principia so that it appiies to dynamie problems. The variational technique is first derived in generał for an elastic system, and then spe-crfically tailored to an open cylindricai cantilevered shell. The technique is implemented by first finding a generał solution which satisfies the equations of motion for a cylin-drical shell. A method is then formulated to use this generał solution to construct a set of trial solution functions. With the variational method. the coefficients to this trial solution function are then calculated so that the function not only satisfies the equations of motion, but also the boundary conditions around the four edges of the shell.

84-1739

Sound Trananiaaion through Layered Cylindricai Shells with Applied Damping Treatment

S. Narayananand R.L. Shanbhag Indian Inst. of Tech., Madras-600 036. India. J. Sound Vib., J£J4), pp 541-558 (Feb 22. 1984) 9 figs. 5 tables, 23 refs

Key Words: Shells, Cylindricai shells, Sandwich structures. Sound wsves, Wave transmission, Demped structures

Sound transmission through closed circular cylindricai shells with unconstrained damping treatment and sandwich shells with constrained damping treatment is considered in an acoustoelastic formulation in which the fuli interaction between the tfructural yibration and the internal cavity pressure field are taken into account. Only the axisymmetric modes of vft>ration of the shell are considered in an initial formulation. The ttructurai raaponaa and tha tound tran#-mission charecteristics for an external random pressure field are computed through an efficient matrix inversion procedura.

84-1741

New Method of Analyzing Yibration of Cracked Cylindricai Shells

R. Solecki

Dept. of Mech. Engrg., Univ. of Connecticut, Storrs, CT, Rept. No. UCONN-ME-82-83-ONR-1, 72 pp (Dec 26.1983)

AD-A136 637

Key Words: Ptatas. Shells. Cylindricai shells, Cracked media

The method of Fourier trensformation of functions with lines of discontinuity and with built-in point singularities. is applied to analysis of yibration of cracked rectangular platet and of cracked cylindricai shells of rectangular plan-form. Application of the above method in conjunction with Green-Gauss Theorem leeds to an infinłte system of lineer algebraic eguations. Numerical exsmples include a piąte with a perallel crack, a piąte with a diagonal crack and a shell cracked at the apex.

84-1740

Yariational Method for Calculating the Natura! Frequencies and Modę Shapes of a Cantilevered Open Cylindricai Shell

84-1742

Free Yibration of a Point-Supported Circular Cylin-drical Shell

T. Irie, G. Yamada. and Y. Kudoh