A spectral-Tchebychev solution technique for determining vibrational behavior of thick plates having arbitrary geometry

Phononic crystal investigation using a fluid-structure circular cylindrical shell spectral element

Exact frequency-domain spectral element model for the transverse vibration of a reangular Kirchhoff plate

Exact spectral element model for rectangular membranes subjected to transverse vibrations

Modeling beam reinforced thin plates at mid and high frequencies through the most commonly used methods such as finite and boundary element methods frequently leads to unsatisfactory results, since the accuracy of these methods depends on the relation between the dimensions of the elements in which the structure was discretized and the wavelength. Due to this characteristic, the modeling using these techniques will require that the size of the elements becomes smaller as the frequency increases, while its number needs to be increased. For structures that are usual in some areas, like the aerospace industry, this will be possible only with an unreasonable computational effort, which is responsible for restricting the use of these methods practically to low-frequency applications. Semi-analytical methods such as the spectral element method do not need mesh refinement at higher frequencies, but they were very limited in the geometries and boundary conditions that can be treated. This paper presents a spectral element for rectangular thin plates reinforced symmetrically along the sides with Euler beams, which can be used to model plates with arbitrary boundary conditions. The method was verified by comparing its results with those obtained from a Finite Element model.

/pdf/on-the-modeling-of-beam-reinforced-thin-plates-using-the-32pdhxxnr9.pdf

On the Modeling of Beam Reinforced Thin Plates Using the Spectral Element Method

In the mid-frequency range, numerical methods such as the finite and boundary element methods are not the most suitable for structural dynamic analysis as mesh refinement leads to models that are often too large. Semi- analytical methods such as the spectral element method do not need mesh refinement at higher frequencies, but, until now, they were very limited in the geometries and boundary conditions that could be treated. This paper develops a spectral element for thin plates based on a high precision finite element proposed by Kulla, which can be used to model plates with any boundary conditions. The results obtained are compared with others from different methods presented in the literature.

/pdf/modeling-kirchhoff-plates-with-arbitrary-boundary-conditions-30cdgx1wuq.pdf

Modeling Kirchhoff plates with arbitrary boundary conditions by the spectral element method

This work studies the influence that the shape of the section of a column immersed in a watercourse has in relation to the hydrodynamic forces that arise due to fluid-structure interaction. The data about São Paulo state rivers’ flows and bridges were revised in order to determine a critical flow rate and choose the cross sections study cases. The simulations made with the ANSYS Fluent software allowed it to obtain the parameters of pressure and drag present in the surface of the column, and these values were used as a criterion to analyze the performance of different cross sections. The model was validated by comparison with the results from other authors in order to guarantee reliability to the study. The values obtained for different cross sections were compared to standardized values recommended by the Brazilian code NBR 7187/2003, when available.

Study of the influence of columns’ geometry in hydrodynamic loads

Precise predictions of dynamic behavior in complex structures demands numerical models with very high accuracy. Generally complex structural systems are modeled using numerical methods such as finite difference method, finite element method, and boundary element method. The last one has emerged as an alternative technique, well suited to approximate the solution of a large class of engineering problems. However, the actual dynamic performance of such structures rarely match with his numerical models. The solution of this problems resides in the development and evaluation of structural model update methods. In this paper a technique based on measured frequency response function (FRF) data along with a correlated analytical boundary element model is presented. The correlation measurement/model data are made throughout an objective function involving the sum of squares of the difference between the measured and estimated FRFs data. Numerical studies considering various assumptions for the boundary element model updating scheme are presented. The boundary elements results are compared with those obtained by finite element method.

Nivaldo Benedito Ferreira Campos

Papers

On the Modeling of Beam Reinforced Thin Plates Using the Spectral Element Method

Modeling Kirchhoff plates with arbitrary boundary conditions by the spectral element method

Study of the influence of columns’ geometry in hydrodynamic loads

Boundary element model updating in structural dynamics

A Collocation Approach for the Spectral Element Method