Assistant professor, Memphis State University, Memphis, TN
Associate professor, Virginia Polytechnic Institute and State University, Blacksburg, VA
Professor and director, University of Texas at San Antonio, San Antonio, TX
Pages: 17 Published: Jan 1990
Unidirectional fiber-reinforced plastic (FRP) composite lamina, made from Kevlar 49 fibers and Fiberite 7714A epoxy, were characterized for nonlinear thermoviscoelastic response using the time-temperature superposition principle (TTSP). Mechanical static creep and creep recovery tests were performed using strain gages on 0°, 10°, and 90° unidirectional specimens at numerous temperature and stress levels. Master curves and shift factor functions for all four orthotropic material properties (fiber direction S11, fiber/transverse coupling direction S12, transverse direction S22, and shear S66 compliances) were obtained. Results were used in a numerical procedure to predict the viscoelastic response of general laminates. Predictions are compared with actual test results on selected two, three, and four fiber direction laminates made from Kevlar/epoxy.
composite materials, creep, Kevlar/epoxy, viscoelasticity, accelerated characterization, lamination theory, time-temperature superposition principle
Paper ID: STP24127S