Monday  |  Salon 11  |  09:00 AM–09:20 AM

#15582, Statistical Life Prediction of Unidirectional CF/PP Laminates under Tension and Bending Loads by Accelerated Testing Methodology

Our developed accelerated testing methodology (ATM) based on the matrix resin viscoelasticity for the failure life prediction of fiber reinforced polymers (FRP) was applied to the statistical prediction of long-term creep and fatigue failure life under tension and bending loads for the longitudinal direction of unidirectional CF/PP laminates. First, the master curve of relaxation modulus of matrix resin in the wide range of time at a reference temperature was obtained by applying the time-temperature superposition to the results of DMA and creep tests measured at various temperatures which is the most important item for long-term reliable prediction. Second, the shape and scale parameters of tensile and flexural static strengths at a reference time and temperature and the viscoelastic parameter were experimentally determined through the static tension and bending tests for CF/PP laminates. The statistical creep failure times for CF/PP laminates under tension and bending loads were predicted by substituting the parameters determined by the static tension and bending tests into the formulation of ATM, and the validity of predicted results was confirmed by the creep tension and bending tests for CFRP laminates at various load level at several temperatures. Third, the master curve of non-dimensional fatigue strength-number of cycles to failure (S-N master curve) was constructed by the fatigue tension and bending testes for CF/PP laminates at various temperatures and frequencies based on the viscoelasticity of matrix resin. Finally, the long-term creep and fatigue strengths under tension and bending loads for CF/PP laminates were statistically and reliably predicted. As results, the effect of viscoelasticity of matrix resin on the creep and fatigue failure lives of CF/PP laminates under bending load was larger than those under tension load. The creep failure strength of CF/PP laminates under bending load decreases remarkably with increasing time and temperature comparing to that under tension load. On the cases of fatigue failure life of CF/PP laminates, the decreasing of fatigue strengths is not so remarkably with increasing time and temperature in both tension and bending loads comparing with the cases of creep failure life, and the S-N master curves shows characteristic behavior for each of tension and bending loads.

Yasushi Miyano   Kanazawa Institute of Technology
Masayuki Nakada   Kanazawa Institute of Technology
Yoko Morisawa   Kanazawa Institute of Technology
Taiga Nonaka   Kanazawa Institute of Technology
Takeharu Isaki   Mitsui Chemicals, Inc.
Taiki Hirano   Mitsui Chemicals, Inc.
Kiyoshi Uzawa   Kanazawa Institute of Technology