On a new mixed-hybrid variational principle and analysis of upper and lower solutions by the isolated element method

A new mixed and hybrid variational principle is proposed for the elasticity in this paper. This principle is composed from the potential energy functional and the complemental energy functional that the pair of these energy are constrained by a formula. Using this principle for the analysis of the solid mechanics, that is discretized or not, stress and displacement be able to analyze at the same time. Upper and lower bounds of numerical stress be able to analyze by the isolated element method that is based on the proposed principle. © 2020 by the Japan Society for Computational Engineering and Science.