Getting It Right with Composites

With composites now a mainstay in most new aircraft designs, the engineering emphasis has switched from understanding if they work to thinking through the most efficient way to manufacture them, such as using design-for-manufacturing software.

“Composite design and analysis is a highly integrated activity,” said Chris Gear, Chief Technology Officer & Senior Technical Fellow for GKN Aerospace. He noted that how composite material is placed, how it moves, how it cures, and the quality and conformance of the product are all interrelated. All of these factors are considered in the final release of the data for manufacturing, according to him, aided by design-for-manufacturing (DFM).

Complicating manufacturing optimization is the very nature of advanced composites, requiring a unique design process, unlike isotropic, homogenous metal. Controlling fiber orientation and number of layers of fiber embedded in a plastic matrix is vital for its performance. Initial CAD definitions that specify the outer and/or inner mold lines of the part require further definition of material type, fiber orientation, stack-up order, balance, symmetry, drop-offs, splices, and darts.