Optimal Design of Unitized Structures Using Response Surface Approaches

摘要

Developments in rapidmanufacturing techniques such as electron beamfreeform fabrication have made it easiernto manufacture objects with complex shapes (like panel with curvilinear stiffeners). In this paper, designnoptimization of stiffened panels is carried out using different types of response surfaces. Placement and sizingnvariables are optimized using integrated high-performance, commercially available software. The proposednapproach has two optimization loops. The sizing optimization is carried out in the first loop through finite elementnanalysis using gradient-based optimization method for different placement variables. In the second loop, optimalnplacement of stiffeners is carried out using response surfaces. Because of response surface construction using wholendesign space, the proposed approach does not suffer fromgetting trapped in a localminima. The proposed approachnis applied to square panels subjected to in-plane biaxial and uniform surface pressure loadings. Panel weight isnminimized with buckling, displacements, and stress constraints. An approach to perform both placement and sizingnoptimization of panels with curvilinear stiffeners is also discussed and a surrogatemodel is developed for placementnand shape optimization of stiffeners.