Elastic characterization of isotropic plates of any shape via dynamic tests: Theoretical aspects and numerical simulations

In this paper the feasibility of application of a numerical-experimental procedure for determining the elastic constants of isotropic thin plates with contours of any shape is investigated. The procedure is based on an optimization process that determines the values of the unknown elastic parameters by minimizing the difference between the resonant frequencies of the plate under examination calculated with a numerical model and those measured experimentally. The identification of all the elastic constants is carried out simultaneously, not destructively and in a single test. The effectiveness of the procedure and its sensitivity to measurement errors have been investigated by means of a series of numerical simulations executed on plate models of various geometry.     

Parametric vibrations of orthotropic plates with complex shape

The paper proposes a method to study the parametric vibrations of orthotropic plates with complex shape. The method is based on the R-function theory and variational methods. Dynamic-instability domains and amplitude–frequency responses for plates with complex geometry and different types of boundary conditions are plotted     

Non-linear axisymmetric static analysis of orthotropic thin annular plates

This investigation deals with the geometrically non-linear axisymmetric static analysis of elastic orthotropic thin annular plates subjected to uniformly distributed and ring loads. Non-linear differential equations in terms of the transverse displacement w and stress function ψ have been employed. Both w and ψ are expanded in finite power series and the orthogonal point collocation method has been used to obtain discretised algebraic equations from the governing differential equations. Results have been presented for annular plates with and without a rigid plug in the hole; simply supported, clamped and free outer edge conditions; three orthotropic parameters β; two annular ratios and two loading conditions. Results have also been presented illustrating the effect of an elastic rotational constraint at the edge and the effect of a prescribed inplane displacement of the edge.     

Nonlinear axisymmetric static and transient analysis of orthotropic thick annular plates

Summary This paper deals with the geometrically nonlinear axisymmetric static and transient response of moderately thick cylindrically orthotropic circular plates subjected to uniformly distributed and ring loads. Immovable clamped and simply supported annular plates with and without a rigid plug subjected to static and step function loads have been considered. Shear deformation and rotary inertia have been included. Orthogonal point collocation method and Newmark- scheme have been employed to solve the differential equations expressed in terms of transverse displacement , shear rotation and stress function . The effect of transverse shear has been investigated for isotropic and orthotropic plates. A simple approximate method has also been used to predict the maximum dynamic response to step loads from the results for static loads.

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Nichtlineare, axialsymmetrische, statische und dynamische Analyse orthotroper, dicker Kreisringplatten

Übersicht Es wird das geometrisch nichtlineare, axialsymmetrische Verhalten orthotroper Kreisring-platten unter gleichmäßig bzw. ringförmig verteilten Lasten untersucht. Eingespannte und gelenkig gelagerte Platten mit oder ohne starrem Pfropfen unter statischer oder dynamischer Belastung werden behandelt, wobei Schubdeformation und Drehträgheit berücksichtigt werden. Eine Kollokationsmethode und das Newmarksche -Schema werden angewendet, um die Differentialgleichungen für die Durchbiegung , die Verdrehung und die Spannungsfunktion zu lösen.

     

Solving three-dimensional static problems for orthotropic plates with sliding edge conditions

Homogeneous solutions of the elastic equilibrium equations for orthotropic plates are obtained. The normal displacement and tangential stresses on the flat edges of the plates are zero. Methods to integrate the governing equations are proposed. An explicit analytic solution for the stress state of a layer with circular or elliptic cavities under a load constant throughout the thickness is obtained Translated from Prikladnaya Mekhanika, Vol. 44, No. 8, pp. 114–125, August 2008.     

Large deflection static and dynamic analysis of isotropic and orthotropic annular plates

In the present paper, Chebyshev series are employed to obtain the non-linear static and dynamic response of isotropic and orthotropic annular plates. The non-linear partial differential equations obtained from von Karman's large deflection plate theory have been solved by using the Chebyshev series in the space domain and the Houbolt numerical integration scheme in the time domain. Two different sets of boundary conditions of the annulus are investigated and detailed numerical results have been obtained for different cases of orthotropy and geometry.     

Stability of annular orthotropic plates

It is assumed that the orthotropy of the plate material is rectangular or polar, and a uniformly distributed, external compressive or tensile load is applied to the internal boundary of the plate. Stability is analyzed by the Ritz method with the use of Alfutov-Balabukh and Bryan energy criteria. Diagrams of the critical external load and buckling modes as a function of the plate dimensions are given. Novosibirsk State Technical University, Novosibirsk 630092. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 2, pp. 166–170, March–April, 2000.     

Limit analysis of orthotropic plates

The limit analysis problem for plates in bending is considered. The failure criterion for the material is assumed as orthotropic, with possible non-symmetric strength properties. According to Kirchhoff’s hypothesis, the plate is conceived as a superposition of layers, individually in plane stress situation, and continuity is enforced by means of a kinematic assumption. By exploiting previous results, recently established by the authors, the expression of the dissipation power per unit plate area is defined on this basis and the kinematic (upper bound) theorem of limit analysis is cast in a form suitable for numerical solutions. To this purpose, efficient algorithms successfully employed in the isotropic case can be used with minor modifications. The effectiveness of the procedure is demonstrated by solving some homogeneous plate examples. Results permit the assessment of the influence of different aspects, such as the ratio between strengths along the orthotropy directions, the tensile to compressive strength differential and the inclination of the orthotropy axes with respect to the sides. The effects of in-plane edge constraints are also discussed and it appears that they are emphasized considerably by anisotropy. Even if referred to specific cases, some conclusions can be regarded as fairly general.     

The deformed shape of isotropic and orthotropic plates subjected to bending moments distributed along the edges

Meccanica - The paper focuses on the deformation behaviour of isotropic and orthotropic plates subjected to bending moments distributed along the edges, two couples M0 and ?M0 along the...     

Transient vibration of thin viscoelastic orthotropic plates

This article deals with solutions of transient vibration of a rectangular viscoelastic orthotropic thin 2D plate for particular deformation models according to Flu¨gge and Timoshenko-Mindlin.The linear model,a general standard viscoelastic body,of the rheologic properties of a viscoelastic material was applied.The time and coordinate curves of the basic quantities displacement,rotation,velocity,stress and deformation are compared.The results obtained by an approximate analytic method are compared with numerical results for 3D plate generated by FEM application and with experimental investigation.