Vibration Of Cylindrical Panels Research Articles

VIBRATION OF TWISTED AND CURVED CYLINDRICAL PANELS WITH VARIABLE THICKNESS

A numerical procedure, with an exact strain–displacement relationship of twisted and curved cylindrical panels having variable thickness derived by considering the Green strain tensor on general shell theory, is presented using the principle of virtual work and the Rayleigh–Ritz method with algebraic polynomials as in-plane and transverse displacement functions. The accuracy and applicability of the procedure are verified by comparing the present results with previous experimental and theoretical results for several panels. The effects of variation ratio of thickness in chordwise and lengthwise directions, twist, and curvature both in two directions aforementioned on vibrations of cylindrical panels are studied in detail, and typical vibration mode shapes are plotted to demonstrate the effects.

Bifurcation Analyses in the Parametrically Excited Vibrations of Cylindrical Panels

We consider parametrically excited vibrations of shallow cylindrical panels. The governing system of two coupled nonlinear partial differential equations is discretized by using the Bubnov–Galerkin method. The computations are simplified significantly by the application of computer algebra, and as a result low dimensional models of shell vibrations are readily obtained. After applying numerical continuation techniques and ideas from dynamical systems theory, complete bifurcation diagrams are constructed. Our principal aim is to investigate the interaction between different modes of shell vibrations under parametric excitation. Results for system models with four of the lowest modes are reported. We essentially investigate periodic solutions, their stability and bifurcations within the range of excitation frequency that corresponds to the parametric resonances at the lowest mode of vibration.

Natural vibrations of parallelogram cylindrical panels

In the present study, the problem of the natural vibrations of cylindrical panels restrained along the entire perimeter is examined in the linear statement. The solution of this problem presents significant difficulties caused by the skew edges of the panels. The literature contains only investigations of parallelogram plates and cylindrical panels of rectangular planform, where various methods are employed: the Treffits energy method [1], the Bubnov-Galerkin variational method using small-beam functions [2], the Rayleigh-Ritz method [3], the Bubnov-Vlasov variational method in conjunction with the modified method of successive approximations [4], the finite-difference method [5], etc. The vibrations of cylindrical panels of rectangular planform have been investigated by the Bubnov-Papkovich method [6], the Bubnov-Galerkin-Vlasov method [7], and in a number of other studies.

Vibrations and stability of cylindrical panels with elliptical cross section

The free vibrations of cylindrical panels with elliptical cross section subjected to an initial stress state are investigated. The buckling problem of the panel under the stress state considered is studied as special case of the free vibration problem.

Dynamic behaviour of a simply supported circular cylindrical panel subjected to an initial bending moment

The vibration of cylindrical panels with simply supported boundary conditions in the presence of an initial bending moment is investigated. The analysis is based on the theory of Herrmann and Armenàkas. The results for the stability and free vibration of the panels are obtained as special cases.

Stabilization of the motion of a cylindrical panel

1. We have formulated and investigated theoretically a set of problems related to the stabilization of transverse vibrations of cylindrical panels: an analytic construction of a block diagram of an ACS, the study of autooscillations and forced oscillations of a panel—control system. 2. The introduction of an ACS is of practical value since the possibility of the variation of the parameters of the feedback circuit for a specific deformable objectumakes it possible to obtain dynamic processes with the desired amplitude—frequency characteristics.

Vibration of Cylindrical Panels Carrying a Concentrated Mass

Vibration of Cylindrical Panels Carrying a Concentrated Mass

Natural Vibrations of Cylindrical Panels

In terms of Lame parameters, basic equations and energy expressions are formulated for the moderately thick-walled shells. The general formulations are then specialized for cylindrical panels. The frequency determinants are obtained by the Rayleigh-Ritz procedure. Both straight and curved characteristic beam functions have been utilized to obtain the frequencies of shell panels having different aspect ratios and central angles subtended by the curved edges and results compared. Effects of rotatory inertia, shear deformations as well as a few Poisson-type boundary conditions have also been considered and discussed.