Damping Loss Factor Determination of Glass and Graphite Fiber Composites
Research development technical evaluation rept. Jan-Jul 1989
DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT
Pagination or Media Count:
Material damping of laminated composites is experimentally determined using a cantilever beam test with an impulse excitation. Data acquisition and manipulation is carried out using both an IBM PC-AT and a GenRad 2500 Series FFT Analyzer. Unidirectional continuous fiber 0 and 90 degree laminates were fabricated from glassepoxy Hercules S2-Glass3501-6, graphiteepoxy Hercules AS43501-6 and graphitepolyetheretherketone ICI AS4PEEK APC-2 to investigate the effect of fiber and matrix properties as a function of frequency, up to 1000 Hz., on the damping of composites. The S2-glass3501-6 composite had a higher loss factor than the AS43501-6 exhibiting a linear increase with increasing frequency and the loss factor for the S2-glass varying nonlinearly with frequency. The 90 degree material exhibited a higher damping loss factor than the 0 degree, varying nonlinearly with increasing frequency. In the 90 degree orientation, the glass fiber composite had loss factors that was approximately a factor of 2 greater than the 0 degree orientation. The 0 degree AS4PEEK had a loss factor that was approximately equal to that of the 0 degree AS43501-6. The 90 degree AS4PEEK had a loss factor that was approximately 50 less than the AS43501-6 and 25 greater than the S2-glass3501-6. Keywords Vibration damping Structural composites Joints Shipbuilding.
- Laminates and Composite Materials
- Marine Engineering