Refined shell model for the linear analysis of isotropic and composite elastic structures

A refined finite element shell model has been developed in this work using an eight-nodes element with nine degrees of freedom for each node. This model enhances the classical shell approaches by including the transverse normal strain. The three displacement components are quadratically expanded in the thickness direction, therefore the transverse shear and normal strains effects are included in such a model making it suitable for thin and thick multilayered composite structures. The transverse normal strain is linear in the thickness direction z and the related shell theory is free from Poisson locking. Finite element locking mechanisms (shear and membrane locking) have been opportunely corrected: good convergence rate has been shown for the considered shell problems (with various geometries, thickness ratios and stacking layer sequences). No shear correction factors are requested.