Elkin, R. A.
Senior structures engineerstaff engineer, Textron's Bell Aerosystems CompanyRohr Corp., BuffaloRiverside, N. Y.Calif.
Senior materials engineer, Textron's Bell Aerosystems Co., Buffalo, N. Y.
Hanley, D. P.
Chief, Textron's Bell Aerosystems Co., Buffalo, N. Y.
Pages: 15 Published: Jan 1969
The strength properties of a unidirectional lamina are essential inputs to the design of efficient composite airframe structural elements. To achieve the reliability required for such structures, these properties must be determined experimentally. A program was undertaken to characterize the static tensile, compressive, and in-plane shear strengths of Thornel-50, Morganite Type II, and HMG-50 unidirectional graphite fiber/resin matrix laminates. Test results show that the Morganite fiber composites have significantly higher compressive, shear, and transverse tensile strengths than Thornel or HMG fiber composites. However, for longitudinal tension, the Thornel laminates have a slight strength advantage over the other two materials. Calculated strength envelopes for a typical airframe component laminate are presented as a convenient means of material comparison. Correlations of laminate strengths with fiber content are shown, and optimum fiber contents for Thornel-50 laminates are estimated. Test methods used are reported, and differences in observed failure modes with the various materials are discussed. Test panel fabrication procedures, materials acceptance, and nondestructive inspection techniques are reviewed also. Composite strengths plotted as a function of qualitative ultrasonic inspection ratings show a promising correlation.
graphite, fiber composites, test methods, ultrasonics, strength, mechanical properties, fabrication, inspection, laminates, tension, compression, shear, resin, processes, unidirectional, longitudinal, transverse, failure mode, evaluation, tests
Paper ID: STP49825S