Mechanical engineerMember of ASTM, National Bureau of Standards, Washington, D.C.,
Tensile creep tests were performed at 75°F (24°C) and 300°F (149°C) on 26 specimens cut from ±30-deg and ±45-deg laminates of boron/epoxy composite material to characterize the creep behavior of these materials. A linear viscoelastic laminate theory proposed by McQuillen was compared with the experimental data for the tests run at 75°F (24°C). The predicted creep strains differed greatly from the measured values, indicating that the linear theory is not applicable to laminates with these filament orientations. A general creep equation of the form ε = kσmtn was fitted to the experimental data with excellent correlation. The stress exponents was fitted to the experimental data with excellent correlation. The stress exponents m varied from 1.79 to 5.17 for the four series of tests, thus characterizing the nonlinear behavior of boron/epoxy laminates with these filament orientations.
Paper ID: JTE11700J