Monday  |  Salon 11  |  10:20 AM–10:40 AM

#15572, Statistical Life Prediction of Unidirectional CFRP under Creep and Fatigue Tension Loads by Accelerated Testing Methodology

The mechanical behavior of matrix resin of CFRP exhibits time and temperature dependence, called viscoelastic behavior, not only above the glass transition temperature, but also below the glass transition temperature. Consequently, it can be presumed that the mechanical behavior of CFRP depends strongly on time and temperature. The accelerated testing methodology (ATM) for predicting statistically long-term creep and fatigue strengths of CFRP was established by the authors.
This study examines the statistical life prediction of unidirectional CFRP under creep and fatigue tension loads by our developed ATM. Two kinds of resin impregnated carbon fiber strand (CFRP strand) are selected as unidirectional CFRP which consist of two kinds of PAN based carbon fiber, Torayca T300 and Torayca T700, and thermoplastic epoxy (TPEP) as matrix resin. Statistical life of two kinds of CFRP strand under creep and fatigue tension loads are evaluated by ATM and these characteristics are discussed.
The static tensile strengths of two kinds of CFRP strand were measured statistically at various constant temperatures and the relaxation moduli for matrix resin were also measured at various constant temperatures. Then the statistical creep tensile strengths for two kinds CFRP strand were predicted by substituting the measured data into the formulae of these strengths on our developed ATM. The validity of prediction was cleared by compared with the creep tensile strengths measured directly by creep tests. The master curves of non-dimensional fatigue strength-number of cycles to failure (S-N master curve) were constructed by the fatigue tension tests for two kinds of CFRP strand at various temperatures based on our developed ATM. Finally, the long-term creep and fatigue strengths under tension load for two kinds of CFRP strand could be statistically and reliably predicted and the characteristic behavior of creep and fatigue strengths for these CFRP strands could be clarified.

Masayuki Nakada   Kanazawa Institute of Technology
Yasushi Miyano   Kanazawa Institute of Technology
Ryohei Tomita   Kanazawa Institute of Technology
Naoya Kawamura   Kanazawa Institute of Technology
Yoko Morisawa   Kanazawa Institute of Technology
Kazuro Kageyama   Kanazawa Institute of Technology