Linear equality constraints in finite element approximation

✍ Scribed by Barna A. Szabo; Tony Kassos

• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 915 KB
• Volume: 9
• Category: Article
• ISSN: 0029-5981
• DOI: 10.1002/nme.1620090306

✦ Synopsis

Abstract

The typical numerical problem associated with finite element approximations is a quadratic programming problem with linear equality constraints. When nodal variables are employed, the coefficient matrix of the constraint equations, [A], acquires a block‐diagonal structure. The transformation from polynomial coefficients to nodal variables involves finding a basis for [A] and computing its inverse.

Simultaneous satisfaction of completeness and C^1^ (or higher) continuity requirements establishes linear relationships among the nodal variables and precludes inversion of the basis by exclusively element‐level operations.

Linear dependencies among the constraint equations and among the nodal variables can be evaluated by the simplex method. The computational procedure is outlined.