Hybrid composite-material (fiber/matrix) structures of a proposed type would incorporate recently developed polybenzoxazole (PBO) fibers that feature high strengths and high moduli of elasticity and which can be made in much thinner sections than are possible with graphite fibers. The PBO fibers could be used, for example, in skins, face sheets, or panels, any or all of which could be made as multiple-angle-ply layups.

In comparison with similar structures made from graphite fibers to satisfy a given set of strength and stiffness requirements, those made from PBO fibers to satisfy the same set of requirements could be thinner. In a typical application, PBO-fiber laminated face sheets or skins would be bonded to graphite stiffeners or honeycomb cores to make hybrid composite stiffened sandwich structures thinner and less massive than the corresponding structures made with graphite (only) fibers, due to the thinner sections possible with PBO fibers.

This work was done by Joseph Lewis of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Materials category.