Time-and temperature-dependent compressive behavior of woven carbon fabric reinforced polyamide composite laminate

Plain woven carbon fabric reinforced polyamide (CF/PA) composite laminate was developed using hot-pressed processing with a vacuum-assisted system. Temperature-dependent mechanical properties of the CF/PA composite laminate under longitudinal compressive loading were examined. The compressive mechanical properties of the composite laminate decreased considerably with increasing the temperature to 120 degrees C. The compressive strength and strain at maximal stress reduced rapidly below 80 degrees C, while the compressive modulus declined slightly underneath 50 degrees C. The glass transition temperature of the CF/PA composite was found to be about 50 degrees C by the differential scanning calorimetry, which almost corresponded to the slight reduction of the elastic modulus at temperatures below 50 degrees C. The time-dependent creep behavior of the CF/PA laminate under compressive loading at isotherms between 25 degrees C and 50 degrees C was studied. Creep strains of the CF/PA composite samples increased with rising temperature. The smooth creep compliance master curve of the CF/PA composite was obtained by shifting short-term creep compliance curves using the time-temperature superposition principle. The master curve provided a creep prediction to 961.6 days with the measured data in only 12.5 days.