Best Theory Diagrams for Shell Finite Elements

This paper presents a novel methodology to construct refined shell finite elements. The approach makes use of the axiomatic-asymptotic method and leads to the definition of Best Theory Diagrams. The typical results provided by the proposed methodology are the minimum set of unknown variables required to meet a given accuracy level if compared to 3D results and the best accuracy available for given computational cost. Also, the current approach can serve as a tool to assess the accuracy and computational accuracy of any structural model. The numerical results focus on isotropic and multilayer shells and highlight the importance of specific higher-order terms in refined models. Via the appropriate choice of the effective terms, the present technique succeeded in halving the number of nodal degrees of freedom without significant accuracy degradations.