Partial Fourier approximation of the Lamé equations in axisymmetric domains

• Main Authors: Nkemzi, Boniface, Heinrich, Bernd
• Language: English
• Published: Technische Universität Chemnitz 2005
• Subjects: info:eu-repo/classification/ddc/510; ddc:510; A-priori-Abschätzung; Finite-Elemente-Methode; Lamé-Gleichung; Lineare Elastizitätstheorie; Randwertproblem; axisymmetric domain; partial Fourier method
• Online Access: http://nbn-resolving.de/urn:nbn:de:swb:ch1-200501145; https://monarch.qucosa.de/id/qucosa%3A18362; https://monarch.qucosa.de/api/qucosa%3A18362/attachment/ATT-0/; https://monarch.qucosa.de/api/qucosa%3A18362/attachment/ATT-1/; https://monarch.qucosa.de/api/qucosa%3A18362/attachment/ATT-2/

In this paper, we study the partial Fourier method for treating the Lamé equations in three-­dimensional axisymmetric domains subjected to nonaxisymmetric loads. We consider the mixed boundary value problem of the linear theory of elasticity with the displacement u, the body force f \in (L_2)^3 and homogeneous Dirichlet and Neumann boundary conditions. The partial Fourier decomposition reduces, without any error, the three­dimensional boundary value problem to an infinite sequence of two­dimensional boundary value problems, whose solutions u_n (n = 0,1,2,...) are the Fourier coefficients of u. This process of dimension reduction is described, and appropriate function spaces are given to characterize the reduced problems in two dimensions. The trace properties of these spaces on the rotational axis and some properties of the Fourier coefficients u_n are proved, which are important for further numerical treatment, e.g. by the finite-element method. Moreover, generalized completeness relations are described for the variational equation, the stresses and the strains. The properties of the resulting system of two­dimensional problems are characterized. Particularly, a priori estimates of the Fourier coefficients u_n and of the error of the partial Fourier approximation are given.