Vibration of Centrally Stiffened Rectangular Plate

1961 ◽  
Vol 65 (610) ◽  
pp. 695-697 ◽  
Author(s):  
C. L. Kirk

Natural frequencies of free flexural vibration of rectangular plates may, in many cases, be considerably increased by attaching to the plate one or more elastic stiffening ribs parallel to one edge, or by casting or machining the plate and stiffeners integrally.Hoppmann has determined by a semi-empirical method the natural frequencies of an integrally stiffened simply-supported square plate, using the concept of a homogeneous orthotropic plate of uniform thickness having elastic compliances which are equivalent to those of the stiffened plate. Filippov has obtained the exact solution for the fundamental frequency of a simply-supported square plate having a number of equally spaced stiffeners and has considered the effect of point loads applied to the stiffeners in a direction perpendicular to the plane of the plate.

1983 ◽  
Vol 105 (4) ◽  
pp. 363-368 ◽  
Author(s):  
R. J. Dohrmann ◽  
J. N. Wu ◽  
R. E. Beckett

This report describes a parametric approach for the stress analysis of orthogonally stiffened rectangular plates. The analysis assumes that the deflection of an orthogonally stiffened plate is approximated by a homogeneous orthotropic plate of a uniform thickness. Polynomial expressions for maximum deflection for two sets of boundary conditions (all edges clamped and two edges clamped–two edges simply supported) are presented in terms of plate geometry and loading (normal pressure and in-plane forces). A method for computing the stress is presented that permits stresses in the actual orthogonally stiffened plate (that generally does not have a uniform plate thickness) to be determined.


1963 ◽  
Vol 67 (634) ◽  
pp. 664-668 ◽  
Author(s):  
S. Mahalingam

SummaryThe basis of the procedure described in the paper is the replacement of the stiffeners by an approximately equivalent system of line springs. One of two methods may then be used to determine the natural frequencies. A rectangular plate with edge stiffeners, point-supported at the four corners, is used to demonstrate the application of the Rayleigh-Ritz method. Numerical results obtained are compared with known approximate solutions based on finite difference equations. A Holzer-type iteration is employed in the case of a plate with parallel stiffeners, where the two edges perpendicular to the stiffeners are simply supported, the other two edges having any combination of conditions.


1964 ◽  
Vol 15 (3) ◽  
pp. 285-298 ◽  
Author(s):  
Thein Wah

SummaryThis paper presents a general procedure for calculating the natural frequencies of rectangular plates continuous over identical and equally spaced elastic beams which are simply-supported at their ends. Arbitrary boundary conditions are permissible on the other two edges of the plate. The results are compared with those obtained by using the orthotropic plate approximation for the system


1956 ◽  
Vol 60 (544) ◽  
pp. 281-282
Author(s):  
Bertram Klein

Simple Formulae are presented for the first three bending-type and the first torsion-type natural frequencies of any constant thickness cantilever triangular plate. The formulae are derived by a semi-empirical method. Comparison of calculated frequencies with test values indicates agreement within a few per cent. for a variety of plate plan forms.


1962 ◽  
Vol 66 (616) ◽  
pp. 240-241 ◽  
Author(s):  
C. L. Kirk

Recently Cox and Boxer determined natural frequencies and mode shapes of flexural vibration of uniform rectangular isotropic plates, that have free edges and pinpoint supports at the four corners. In their analysis, they obtain approximate solutions of the differential equation through the use of finite difference expressions and an electronic digital computer. In the present note, the frequency expression and mode shape for a square plate, vibrating at the lowest natural frequency, are determined by considerations of energy. The values obtained are compared with those given in reference.


2020 ◽  
Vol 15 ◽  

The induced flexural vibration of slender pipe systems with continuous non uniform cross sectional area containing laminar flowing fluid lying on extended Winkler viscoelastic foundation is considered. The Euler Bernoulli model of the pipe has hinged ends. The inlet flow is considered constant steady that interacts with the wall of the pipe. The mathematical model is developed and its corresponding solution is obtained. The influence of the combination of variation of cross section, foundation stiffness and damping on the critical velocities, complex natural frequencies and stabilization of the system is presented.


Author(s):  
Ciro A. Soto ◽  
Alejandro R. Diaz

Abstract A model to compute average properties for Mindlin plates of rapidly varying thickness was introduced in [SOT93]. The model was designed to be of use in computations of the optimum shape and layout of plates using the technique introduced by Bendsøe and Kikuchi [BEN88]. In this paper we discuss the utilization of the model to determine the optimum layout of plate structures that maximizes a function of the structure’s natural frequencies. A simply supported square plate is used to illustrate the problem of optimization in the presence of repeated natural frequencies. An automotive application is presented to illustrate the usefulness in design practice.


1977 ◽  
Vol 21 (01) ◽  
pp. 24-29
Author(s):  
E. A. Susemihl ◽  
P. A. A. Laura

Polynomial coordinate functions and the Galerkin method are used to determine the response of a thin, elastic, rectangular plate with edges elastically restrained against rotation and subjected to sinusoidal excitation. It is shown that when the flexibility coefficients approach infinity (simply supported edge conditions) the calculated results practically coincide with the exact solution in the case of a square plate when four terms of the expansion are used. Dynamic displacement and bending moment amplitudes are tabulated for different length-to-width ratios, flexibility coefficients, and frequency values.


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