Stacking Sequences for Extensionally Isotropic, Fully Isotropic and Quasi-Homogeneous Orthotropic Laminates

Free vibration analysis of sandwich beams using dynamic finite element (DFE) and FEM formulations

“…This is of particular interest as the use of composites is increasing in the aerospace industry not only because of their high strength to weight ratio, but also because of the ability to have their mechanical properties customized to suit given design criteria such as additional stiffness in a certain direction or a desired coupling. York [44] has published several papers which provide definitive lists of the stacking sequences of layered composites that will yield desired behaviours. These lists can be used as a starting point to develop the DFE theory and methodology required to successfully derive a formulation that can be used to analyze layered composites.…”

Free vibration analysis of sandwich beams using dynamic finite element (DFE) and FEM formulations

“…This is of particular interest as the use of composites is increasing in the aerospace industry not only because of their high strength to weight ratio, but also because of the ability to have their mechanical properties customized to suit given design criteria such as additional stiffness in a certain direction or a desired coupling. York [44] has published several papers which provide definitive lists of the stacking sequences of layered composites that will yield desired behaviours. These lists can be used as a starting point to develop the DFE theory and methodology required to successfully derive a formulation that can be used to analyze layered composites.…”

Quasi-trivial stacking sequences for the design of thick laminates

“…Finally a laminate is quasi-homogeneous if properties (7) and (8) hold simultaneously. Vannucci and Verchery [1] made use of the polar formalism to represent matrices * * * A B D , , and C. They proved that, for the case of a laminate composed of identical plies, the isotropic part of stiffness matrices * B and C automatically satisfies the above equations and only the anisotropic part is thus relevant to the problem.…”

“…In [6] York proposed a list of fully orthotropic angleply laminates and some rules to mix these sequences. In [7] the same author proposed a list of fully uncoupled extensionally isotropic, fully isotropic and quasi homogeneous angle-ply laminates. Despite these list is said to be definitive, counter examples were found, suggesting this is not currently the case.…”