“…In the ZZ models (as in ESL models), the number of kinematic unknowns does not depend on the number of layers. The in-plane displacements combine the smooth (generally, polynomial) functions defined across the entire laminate thickness (linear [37,38,39,40,41,52,55,56,57] or higher-order polynomial, [42,43,44,45,46,51,53,58,59] with the piecewise linear (i.e., zigzag) distributions. The zigzag contributions enable a more realistic modeling of the in-plane crosssectional distortion in multilayered composites, giving rise to a computationally efficient theory for the modeling of relatively thick laminated composite and sandwich structures.…”