A new family of plate/shell finite elements has been conceived. Versions with 3, 4, 6, 8, 9 and 10 nodes are possible. More efficient and more accurate calculation is expected for deflection, stress,thermal stress, buckling, and for vibration which is influenced by all of these. Interlaminar shear stress calculation should be especially improved. Shear deformation is included, which is essential for analysis of composite and sandwich structures. All constant strain states are represented exactly in the new elements. In contrast, the shear-deformable plate/shell elements in current commercial use have spurious shear energy in (what should be) pure bending, and frequently require arbitrary reduction of shear moduli or under-integration to avoid "locking," which can in turn cause zero-energy deformation modes or "mechanisms." The LU71 element in the STARS program used at DFRF is equivalent to the 3-node version of the new family. Safety-critical calculations such as predicting flutter in flight tests requires a higher standard of reliability than most applications. The new family of elements can provide an independent verification based on a different theoretical formulation as well as improve efficiency and accuracy.Commercial Applications:Incorporation in the STARS code used at DFRF may be the first application. It is expected that these superior-quality finite elements will be incorporated in a package of isoparametric elements and licensed for use in one or several of the major American commercial finite element programs. Finite element analysis is a multi-billion-dollar-per-year worldwide industry.
