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A restricted hybrid stress formulation based on a direct finite element method
Author(s) -
Mau S. T.,
Dan H. C.
Publication year - 1986
Publication title -
international journal for numerical methods in engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.421
H-Index - 168
eISSN - 1097-0207
pISSN - 0029-5981
DOI - 10.1002/nme.1620230807
Subject(s) - finite element method , stress (linguistics) , mixed finite element method , displacement (psychology) , degrees of freedom (physics and chemistry) , stiffness matrix , mathematics , element (criminal law) , symmetry (geometry) , extended finite element method , mathematical analysis , structural engineering , engineering , geometry , physics , law , psychology , quantum mechanics , political science , psychotherapist , philosophy , linguistics
A direct method, which uses stress and displacement modes obtained from the governing equations of a problem, is adopted for finite element formulation. It is shown that this method actually leads to a restricted hybrid stress formulation if the displacement modes are changed to ensure symmetry of the stiffness matrix. Through this direct method, however, the problem of selecting the appropriate number of stress modes in the regular hybrid stress model is bypassed. Only the minimum number of modes that are compatible with the number of nodal degrees‐of‐freedom of an element is needed in the formulation. Using more modes only leads to a combination of stress modes, and will not improve the order of performance of the element. It is shown through numerical examples that the restricted hybrid stress formulation leads to well‐balanced elements.