The increased vibration damping capability of bromine-intercalated graphite fibers has been recently reported. Continuing investigation of the use of such fibers in structural composite materials has demonstrated increased flexural damping of unidirectional, brominated P-100 graphite/epoxy composites. Damping was measured at temperatures ranging from − 120 to + 30 °C and at frequencies from 50 to several 100 Hz. As expected on the basis of constituent fiber and matrix damping characterization, the observed damping was both temperature- and frequency-dependent. The peak modal damping ratio observed for pristine fiber composites was 0.8 × 10−3, whereas that exhibited by the brominated fiber composites was 1.6 × 10−3. Theoretical predictions of composite specimen modal damping ratios based on known fiber and matrix properties are in reasonable agreement with experimental data. Discrepancies may be due to imperfect intercalation or to the effects of the fabrication environment on intercalation stability. Analytical results obtained for additional cases and materials indicate that 1) contrary to state-of-the-art design principles, the damping of quasi-isotropic composites made using intercalated graphite fibers could be dominated by fiber damping instead of matrix shear damping; and 2) damping levels of significance could be achieved.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering