Generalized C1 Clough-Tocher splines for CAGD and FEM

The paper generalizes the classical C-1 cubic Clough-Tocher spline space over a triangulation to C-1 spaces of any degree higher that three. It shows that the considered spaces can be equipped with a basis consisting of non-negative locally supported functions forming a partition of unity and demonstrates the applicability of the basis in the context of the finite element method. The studied spaces have optimal approximation power and are defined by enforcing additional smoothness inside the triangles of the triangulation where the Clough-Tocher splitting is used. Locally, over each triangle of the triangulation, the splines are expressed in the Bernstein-Bezier form, which enables one to take the full advantage of the geometric properties and computational techniques that come with such a representation. Solving boundary problems with Galerkin discretization is thus relatively straightforward and is illustrated with several examples. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

The paper generalizes the classical C-1 Clough-Tocher spline space to C-1 spaces of higher degree, demonstrating their applicability in the finite element method. The considered spaces have optimal approximation power and are defined with additional smoothness enforced inside the triangles of the triangulation. Locally, the splines are expressed in the Bernstein-Bezier form, allowing for the utilization of geometric properties and computational techniques. Examples illustrate the straightforward solution of boundary problems with Galerkin discretization.