Coupled quasi-homogeneous orthotropic laminates

Laminate stacking sequence configurations with quasi-homogeneous properties are derived, whereby the inplane and out-of-plane stiffness properties are concomitant. The stacking sequence configurations contain equal-thickness layers and identical orthotropic properties, differing only by their orientations, which are represented by standard angle- and cross-ply combinations. These simplifying assumptions are in fact representative of the common design practice, but help one to identify and isolate a range of highly complex physical coupling responses, which continue to be referred to collectively in the literature as bending-extension coupling. Dimensionless parameters are developed from which the elements of the extensional, coupling, and bending stiffness matrices are readily calculated for any fibre/resin properties. Feasible domains of lamination parameters are also illustrated for each coupling response to complement abridged listings of stacking sequences. Finally, hygrothermally curvature-stable configurations with quasi-homogeneous properties are identified, thus simplifying the manufacture of laminate configurations possessing tailored mechanical coupling responses.