Prof. habil. dr. Rimantas Barauskas
Kauno Technologijos Universitetas, Informatikos fak.
Taikomosios informatikos katedra

On space and time step sizes in ultrasonic pulse propagation modelling
Rimantas Barauskas.

Abstract. The focus of the work is to analyse and improve the accuracy of space and timediscretized rectangular finite element models for transient acoustic and elastic wavepropagation. The propagation of the typical ultrasonic pulse excited on the boundary of theenvironment is under investigation. The dispersion relations of finite element models have beensignificantly improved by selecting appropriate form of the mass matrix. As a consequence, only7-8 elements per wavelength of the main harmonic component oh the pulse suffice to representsatisfactory the wave propagation law. As contraindication for using such an approach is a nondiagonalform of the mass matrix requiring to use iterative methods for solving the linearalgebraic equation system at each time step. However in 2D and 3D cases the increase of theelement size results in considerable savings in memory and computational time even if iterationat each time step is necessary. With increased element size the accuracy requirement instead ofstability is dominating for the selection of the time step. The explicit time integration schemes inthe case of non-diagonal mass matrix have no computational advantage, and implicit ones canbe discussed. The performance of several numerical integration schemes has been evaluated inthis study. From the point of view of combined performance and accuracy criterion, the 3-rdorder generalized Newmark s scheme and time discontinuous Galerkin finite element methodhave been selected.
MiestasCracow
LeidėjasDatacomp
PublikacijaECCM-2001 [elektroninis išteklius] : 2nd European conference on computational mechanics: solids, structures and coupled problems in engineering, Cracow, Poland, June 26-29, 2001, 2001, p. 1-13
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