Topology and Size Optimization of Composite Ply Cargo Door

摘要

Structural optimization has seen accelerateduddeployment throughout all industries in the pastuddecade, largely due to the recognition that tremendousudefficiency gain can be achieved at concept design stageudthrough topology optimization. For composite laminateuddesign a three-phase optimization process is used. Theudtarget of the first phase is the material distribution inudterms of orientation and thickness. This is achievedudthrough topology optimization where thickness of eachud'super-ply' of a unique fiber direction is allowed toudchange freely throughout the structure. As a resultudthickness contour of each fiber orientation is obtained.udA discrete interpretation of the thickness contourudresults in concept design of ply layout and thickness.udThen in Phase-II the interpreted ply-based structuraludmodel is further optimized under all design constraintsudwith discrete design variables representing the numberudof plies of each ply patch. During Phase-III, plyudstacking optimization is performed to refine the designudaccording to detailed manufacturing constraints. Alludmanufacturing constraints are considered throughoutudall three optimization phases. Such requirement wouldudtranslate into percentage requirement during Phase-Iudand II so that a balanced distribution of fiberudorientation is achieved to allow feasible stackingudduring Phase-III. The three-phase optimization processudis illustrated in this paper. A unique modelingudtechnique developed in conjunction with theudoptimization process is the ply-based finite elementudanalysis model where ply entities are defined as sets ofudelements. Then ply layup is specified by a stackuddefinition. In the following sections the procedure isuddemonstrated for one of the preliminary configurationsuddeveloped for the composite cargo door.