ADMISSIBLE MATRIX FORMULATION - FROM ORTHOGONAL APPROACH TO EXPLICIT HYBRID STABILIZATION

Admissible matrix formulation is a patch test approach for efficient c onstruction of multi-field finite element models. In hybrid stress and strain elements, the formulation employs the patch test to identify t he constraints on, respectively, the flexibility and stiffness matrice s which are most detrimental to the element efficiency. Admissible cha nges are introduced to the matrices so as to reduce the computational cost while the element accuracy remains virtually intact. In this pape r, a comprehensive review of admissible matrix formulation is presente d. Finite element techniques seminal to the formulation are also discu ssed.