Damping analysis of composite plates with zig-zag triangular element

A three-node flat triangular element incorporating layerwise zig-zag theory is developed that is suitable for analyzing damped laminated composite structures. By the use of an interdependent kinematic relation, the higher-order shear rotations are replaced by in-plane displacements, a transverse displacement, and section rotations, which result in three translations and two rotations. Natural frequencies and modal loss factors of cantilevered laminated plates with embedded damping layers are calculated with the zig-zag triangular element and compared to the experimental results and MSC/NASTRAN results using a layered combination of plate and solid elements. Frequencies and corresponding loss factors of symmetric and antisymmetric damped laminated cantilever plates as a function of fiber angle are also calculated.