Including manufacturing tolerances in composite design

When composite structures are designed it is important to account for possible variations of design variables. Such variation of design variables are referred to as manufacturing tolerances. Accounting for tolerances early on in the design phase, before the structure is actually manufactured, will reduce the overall lifecycle cost of the structure. In this paper we apply methodologies to incorporate manufacturing tolerances in the optimal design of a composite stiffened panel. A methodology that uses global optimization is used to check if a design has specific manufacturing tolerances. Furthermore, an algorithm for finding the maximal allowable tolerances of a design is a p plied to analyze the tolerances of a design. A procedure to find near-optimal designs that remain feasible within specified manufacturing tolerances is used to obtain designs with tolerances. Designs are obtained for three different objective functions, weight, cost and a combination of weight and cost and a tradeoff analysis is performed.