Quadrangular Nine-Node Superelement for Solving Problems in Statics, Dynamics and Stability of Multilayer Plates

A problem of construction of the quadrangular superelement of a flat multilayer plate on the basis of the triangular six-node finite element of a mixed type with 30 degree-of-freedom is considered. Kinematic and deformation relations are derived with the adoption of Timoshenko’s hypotheses. A technique to construct reduced matrices of the superelement mass and stability by means of introducing approximation functions immediately on the quadrangle is suggested.