Tapered hygro-thermally curvature-stable laminates with non-standard ply orientations

Stacking sequence configurations for hygro-thermally curvature-stable (HTCS) laminates have recently been identified in nine unique classes of coupled laminate with standard ply angle orientations +45°, −45°, 0° and 90°. All arise from the judicious re-alignment of the principal material axis of laminate classes with Bending–Twisting and/or Bending–Extension and Twisting–Shearing coupling; where off-axis material alignment of these parent classes gives rise to distinctly different mechanical coupling behaviour. However, for standard ply angle orientations, HTCS solutions were found in only 8-, 12-, 16- and 20-ply laminates.This article considers non-standard ply angle orientations +60°, −60°, 0° and 90°, which lead to solutions in all ply number groupings for 10 plies and above, thus offering a possibility for ply terminations and hence tapered HTCS laminate designs.