A Design-for-Manufacture Methodology for Incorporating Manufacturing Uncertainties in the Robust Design of Fibrous Laminated Composite Structures

A design-for-manufacture methodology is proposed herein which incor porates manufacturing uncertainties into an optimal design algorithm for structures fabri cated with fibrous composite laminated materials. This article is the first of its kind to de velop a methodology that is focused upon addressing this crucial void in composite materials technologies because variations in the manufacturing parameters are responsible for variations in the properties of the resulting engineered macrostructure and also the principal mechanical properties of the final product. The objective function for this class of stochastic optimization problems and the corresponding probabilistic constraints, which are the kernel of the formulation, are transformed into equivalent deterministic quantities using a Taylor's series expansion and principles of probability and statistics. Although these optimization tools are well-known in the optimal design literature for monolithic materials, their application to design-for-manufacture strategies for composite materials is unique. An illustrative example involving the transient response of a laminated fibrous polymeric composite cantilevered beam demonstrates the significance of employ ing the proposed methodology for optimizing the performance characteristics of a com posite structure characterized by random parameters. The random parameters employed in this example for the fabrication of the composite laminate are ply thickness, fiber orienta tion, and fiber volume fraction.