Abstract
By applying our accelerated testing methodology (ATM) based on the matrix resin viscoelasticity to predict creep and fatigue strengths of carbon fiber reinforced plastics (CFRP), we predicted statistical creep failure times for unidirectional CFRP (UD-CFRP) with matrix resins of two kinds under creep tension load and assessed matrix viscoelasticity effects on the statistical creep life. First, recently developed polypropylene (PP) impregnated CFRP tape (CF/PP tape) and epoxy resin (EP) impregnated CFRP strands (CF/EP strand) were compared after preparation as UD-CFRP specimens. Second, the relaxation moduli for matrix resins of PP and EP were measured at various temperatures. These long-term relaxation moduli were determined based on the time–temperature superposition principle. Third, the statistical static strengths for UD-CFRP of two kinds were measured at a constant strain rate at various temperatures. These statistical creep strengths were predicted by substituting the matrix resin viscoelasticity and the UD-CFRP tensile static strengths into the formulation of ATM. Then the validity of prediction was confirmed by comparing the creep failure times measured under several constant tension loads at arbitrary temperatures. Finally, the long-term creep failure times for UD-CFRP of two kinds were predicted statistically using ATM, thereby clarifying the matrix resin viscoelasticity effects on these creep failure times.
