A general numerical method for the design of multi-ply variable stiffness trajectories of composite laminated shells

This paper introduces a systematic approach for designing multi-ply trajectories in composite variable stiffness laminated shells, with the goal of improving structural performance and preventing manufacturing defects. The method encompasses the entire design process, from initial trajectory generation, trajectory offset, boundary processing, and ply discretization to curvature evaluation, and extends to multi-ply design with the four distinct angle variation patterns. The effectiveness of the proposed multi-ply trajectory design concept is demonstrated through a parabolic composite laminated thick shell. The method is also applied to special cases, such as local modification, hole, and connection problems. All examples confirm that the proposed method successfully avoids common issues such as gaps, overlaps, and wrinkles. The scheme proposed in this paper is systematic and comprehensive, extending the variable stiffness ply design to composite laminated shells and providing strong technical support for the design and manufacture of high performance composite laminated shells.