A BEM BASED ON THE BEZIER/BERNSTEIN POLYNOMIAL FOR ACOUSTIC WAVEGUIDE MODELIZATION

摘要

This paper proposes a novel boundary element approach formulated on the Bezier-Bernstein basis to yield a geometry-independent field approximation. The proposed method is geometrically based on both computer aided design (CAD) and isogeometric analysis (IGA), but field variables are independently approximated from the geometry. This approach allows the appropriate approximation functions for the geometry and variable field to be chosen. We use the Bezier-Bernstein form of a polynomial as an approximation basis to represent both geometry and field variables. The solution of the element interpolation problem in the Bezier-Bernstein space defines generalised Lagrange interpolation functions that are used as element shape functions. The resulting Bernstein-Vandermonde matrix related to the Bezier-Bernstein interpolation problem is inverted using the Newton-Bernstein algorithm. The applicability of the proposed method is demonstrated by solving the Helmholtz equation over an unbounded region in a two-and-a-half dimensional (2.5D) domain.