Effects of Voids on Mechanical Properties of Graphite Fiber Composites
Abstract
The results of an investigation of the effect of voids on the mechanical properties of Thornel 50/Epoxy and Modmor II/5206 Epoxy are discussed and presented. Uni- directional, as well as quasi-isotropic, laminates with symmetrical and nonsymmetrical ply-tacking sequences were fabricated with high and low porosity and subsequently subjected to detailed nondestructive and destructive testing. Longitudinal and transverse flexure and tension, short beam shear, and torsion rod experiments were completed on the two composite systems at 75 and 250 F. Ultrasonic compression and shear wave velocities were measured at discrete locations on a specimen-by-specimen basis, and the observations correlated with observed mechanical properties. An in-depth metallographic characterization of voids was completed on Thornel 50/Epoxy and correlation established for NDT -mechanical properties and voids. These relationships were used to estimate upper and lower bounds on the strength and stiffness envelopes of the unidirectional and angle-ply composites. This permits evaluation of the degradation effects of voids on composite performance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1970
- Accession Number
- AD0727236
Entities
People
- Edward M. Lenoe