A robust four-node quadrilateral element for laminated composite and sandwich plates based on Refined Zigzag Theory

The paper presents a locking-free four-node element for laminated composite and sandwich plates based on Refined Zigzag Theory (RZT). Initially, two RZT-based plate elements are derived using eight-node configurations, achieved by way of standard C0 isoparametric shape functions. In addition, with view improving the modelling extremely thin plates, an anisoparametric is developed in which transverse deflection variable interpolated quadratic polynomial functions, whereas remaining kinematic variables bilinear. A straightforward transverse-shear edge-constraint procedure gives rise to element. further enhancement Element Shear Correction (ESC) factor that from strain-energy matching procedure. resulting (ZQ4c) uses full Gauss quadrature, consistent load vector, mass matrix. Furthermore, ZQ4c stiffness matrix has no spurious zero-energy modes, robust when ultra-thin plates. Several numerical studies carried out demonstrate predictive capabilities four examined this investigation. It concluded highly accurate over wide range material systems span-to-thickness ratios, best performing study.