A Study of the Stress-Strain Behavior of Graphite Fiber Composites to Assess the Stress Levels at Which Significant Damage Occurs.
Final rept. Jul 71-Jul 73,
SOUTHWEST RESEARCH INST SAN ANTONIO TEX
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The purpose of this investigation is to attempt to obtain by experimental means a rigorous definition of the stress level within a composite specimen at which physical damage andor degradation of mechanical properties is initiated and to show that the composite material resistance to subsequent loadings is seriously impaired. Load-introduction problems and compression test methods on tubes of HTSERL 2256 GRAPHITE EPOXY WITH 0C, 090C, 90 or -450C, 90 or -450C, and or - 45C orientations are studied. Additional fatigue data are generated, showing good correlation with significant damage proportional limit stress levels. Maximum strain criterion is used to predict the proportional limit significant damage level and ultimate strength with considerable success. A large number of tubes is fabricated for testing in the balance of the program and a test plan worked out. Author, modified-PL
- Laminates and Composite Materials