Abstract: Ply angular deviation is difficult to completely avoid in the process of prepreg placement, and occurs on one or muti-layer prepreg sheest randomly. It's of engineering significance to study the influence and application method of ply angular deviation on surface profiles of typical curved composite laminates. Under the condition that the total thickness of composite laminates is the same, six group quasi isotropic ply sequences were designed. Through finite element analysis, probability theory method and typical laminate forming verification, the influence of single-layer, two-layer and muti-layer ply angle deviations on the surface profiles and effect rules of curved composite laminates was studied. And the control points for improving surface accuracy of laminates placed by unidirectional prepreg were obtained. The results show that ply angular deviation occurs in outer layer, has a greater influence on surface accuracy of laminates than inner layer, and surface accuracy of laminates decreases with the increase of ply angle deviation. Ply angular deviation directly causes the change of saddle-shaped profile of composite laminate. The saddle profile of laminates can be effectively restrained by controlling the ply angle deviation within 0.25°. Appropriately reducing lamina thickness of prepreg, increasing fiber orientation angles and total plies can effectively reduce the influence of ply angular deviation on composite laminates with limited total thickness.

Key words: fiber orientation angles, angular deviation, composite, laminate, surface profile, angular deviationfactor, finite element analysis