Analise numerica e experimental de fluxo de energia em estruturas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

This work deals with the theoretical, numerical and experimental aspects of energy flow in structures. The mathematical formulation for computation of power flow maps is presented for beams (Euler-Bernoulli and Timoshenko) and plates (Kirchhoff and Mindlin) The physical meaning of active and reactive power is discussed. The reactive intensity is related with the reverberation of energy in the structure, which originates the standing waves or mode shapes. In order to observe this property, the reactive power is separated into its wave components. The reactive maps obtained agree well with the operational modes, indicating the location of the nodal lines. A new technique to localize energy sources based on the divergence of the reactive intensity and the distribution of the potential and kinetic energy densities within the structure is presented. Numerical results are conducted for a beam with a point excitation and a semi-anechoic termination using finite element and spectral element models based on the Euler-Bernoulli beam theory. Numerical simulations are also performed in a square plate hanged with wires at the four corners. The expressions used for computation of power flow are based on the Kirchhoff and Mindlin models. The energy flow maps are obtained experimentally.The measurements conducted in the plate and beam are made using an pulse ESPI (Electronic Speckle Pattern Interferometry) and an LDV (laser Doppler vibrometer), respectively. The results obtained numerically and experimentally are compared. The formulation of two spectral plate elements are reviewed. A spectral element for finite plates with arbitrary boundary conditions in alI edges is proposed

ASSUNTO(S)

holografia interferometrica potencia reativa (engenharia eletrica) metodo dos elementos finitos series de fourier energia vibração ondas elasticas velocimetro doppler por laser

ACESSO AO ARTIGO

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