Abstract:Focusing on the deficiencies of standard-form laminate with extensionshear coupling, such as weak extension-shear coupling, the design method for free-form laminate with extension-shear coupling using the method of optimization design was proposed. Necessary and sufficient material-independent conditions were derived for extension-shear coupled laminates. The stacking sequences of 7-ply to 14-ply free-form laminates with extension-shear coupling were derived. Comparisons were made on buckling strength and robustness of extension-shear coupled laminates. The free-form laminate with extension-shear coupling was used to design structure with extension-twist coupling. Compared to the standard-form laminate, the free-form laminate with extension-shear coupling is worse in buckling strength and robustness, while it’s stronger in coupling. The results also indicate that with an increase in the number of plies, the maximum extension-shear coupling flexibility coefficient of the free-form laminate decreases.