Mechanically coupled laminates with balanced plain weave

Definitive listings of laminate stacking sequences are derived for balanced plain weave laminated materials, assuming each layer is composed of the same material with constant thickness throughout and that standard ply angle orientations 0, 90, and ±45° are adopted; consistent with industrial design practice. A single layer of balanced plain weave material is shown to be immune to thermal distortion following a standard high temperature manufacturing process, which implies that all laminates constructed of this material possess what is commonly referred to as the hygro-thermally curvature-stable or warp-free condition, irrespective of the individual ply orientations used or the laminate stacking sequence definition. A single uncoupled parent laminate class is shown to contain sub-groups with extensionally isotropic and fully isotropic properties that are invariant with off-axis orientation of the principal material axes with respect to the system or structural axes. By contrast a single mechanically coupled parent laminate class is shown to give rise to seven unique forms of coupled laminate through judicious off-axis orientation. Invariant off-axis properties are also identified in coupled laminate designs. Finally, example calculations, abridged stacking sequence listings and design data are presented.