GRAPHITE/EPOXY, BORON-GRAPHITE/EPOXY HYBRID AND BORON/ALUMINUM DESIGN ALLOWABLES

摘要

The results of a study to develop a reliable set of design allowables for type AS GRAPHITE/EPOXY; A HYBRID CONSISTING OF 4.0 MIL BORON/EPOXY AND TYPE AS graphite/epoxy; and boron/aluminum at room temperature and 350 F are presented. Classic lamination theory, supported by testing, has been applied to the filamentary controlled (0/+ OR -45/90) degree family of graphite/epoxy and boron-graphite/epoxy hybrid laminates. The higher transverse layer strength and stiffness of boron/aluminum usually eliminates the need for transverse layers in typical structural applications, therefore the (0/+ or -45) degree family of boron/ aluminum laminates has been chosen for design property determination. Such properties as elastic modulus, shear modulus, in-plane uniaxial strength, in- plane shear strength, coefficients of thermal expansion and major Poisson's ratio have been developed. Equations are presented for laminate strength under the action of combined in-plane loading and for bolted joint behavior. Bonded and brazed joints of these materials are handled by the Grumman joint analysis computer program STPS4. (Author-PL)