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Static analysis of functionally graded composite shells on elastic foundations with nonlocal elasticity theory

Arefi Mohammad, Civalek O.

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

310--326

EN

The aim of this present work is to study the higher-order modelling of a cylindrical nano-shell resting on Pasternak’s foundation based on nonlocal elasticity theory. Third-order shear deformation theory is developed for modelling the kinematic relations, and nonlocal elasticity theory is developed for size-dependent analysis. The principle of virtual work is applied to derive static governing equations. The solution is presented for simply supported boundary conditions in terms of various important parameters. The numerical results including lower- and higher-order longitudinal and radial displacements are presented in terms of nonlocal parameter, two parameters of Pasternak’s foundation and some dimensionless geometric parameters such as length-to-radius ratio and length-to-thickness ratio.

2

A 16-node locking-free Mindlin plate resting on two-parameter elastic foundation – static and eigenvalue analysis

Buczkowski R., Taczała M., Kleiber M.

Computer Assisted Methods in Engineering and Science

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2015

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Vol. 22, no. 2

99--114

EN

The Pasternak elastic foundation model is employed to study the statics and natural frequencies of thick plates in the framework of the finite element method. A new 16-node Mindlin plate element of the Lagrange family and a 32-node zero-thickness interface element representing the response of the foundation are used in the analysis. The plate element avoids ill-conditioned behaviour due to its small thickness. In the case of the eigenvalue analysis, the equation of motion is derived by applying the Hamilton principle involving the variation of the kinetic and potential energy of the plate and foundation. Regarding the plate, the firstorder shear deformation theory is used. By employing the Lobatto numerical integration in which the integration points coincide with the element nodes, we obtain the diagonal form of the mass matrix of the plate. In practice, diagonal mass matrices are often employed due to their very attractive timeintegration schemes in explicit dynamic methods in which the inversion of the effective stiffness matrix as a linear combination of the damping and mass matrices is required. The numerical results of our analysis are verified using thin element based on the classical Kirchhoff theory and 16-node thick plate elements.

3

Analiza dynamiki turbozespołu w ujęciu przemysłowym

Dutkiewicz M., Radulski W., Zelek G.

Tribologia

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2002

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nr 2

399-415

PL

Jednym z głównych kryteriów projektowych dla turbozespołów parowych jest jego stan dynamiczny. Od początku rozwoju konstrukcji turbin parowych inżynierowie kładli duży nacisk na właściwą ocenę stanu dynamicznego turbiny już na etapie prac projektowych. ALSTOM Power Sp. z o.o. od wielu lat używa własnych programów opartych na matematycznym modelu turbiny parowej oraz na doświadczeniach eksploatacyjnych. ARDAS (ALSTOM Rotor Dynamic Analysis System) to najnowszy program do obliczeń dynamicznych turbozespołów parowych. Celem tego artykułu jest prezentacja możliwości systemu programów ARDAS.

EN

The main design criterion of turbine-set is estimating proper dynamic conditions. From beginning of development of design steam turbines engineers have laid great emphasis on proper evaluating of dynamic conditions. Since years dynamic computers software are used for determining or calculating dynamic conditions of turbo-sets in the leading steam turbine companies. ALSTOM Power Sp z o.o for many years has used its own computer programs based on mathematics model of steam turbine and also based on experiences which were collected during many years of operation of turbines. The newest dynamic software used in ALSTOM Power is called ARDAS (ALSTOM Rotor Dynamic Analysis System) which is mentioned in the following elaborate.