Long-term viscoelastic properties of carbon fiber/epoxy composites using tow prepreg strand specimens

Abstract

Carbon fiber/epoxy tow prepreg is an intermediate material for filament winding, consisting of fibers pre-impregnated with a matrix resin in a specific ratio. This study predicted the long-term viscoelastic properties of tow prepreg using DMA and TTSP. Typically, DMA involves applying a wound or laminated flat specimen, but a strand specimen was attempted to predict the characteristics of tow prepreg. The long-term viscoelastic properties were storage modulus, creep compliance, and relaxation modulus. Three test modes were performed in DMA to obtain each result. Smoothly overlapped master curves were obtained in all results. From the master curves, the viscoelastic properties of the material were predicted for 1 year, 10 years, and more extended periods. For 10 years, it was estimated that the storage modulus, creep compliance, and relaxation modulus changed by 7%, 132%, and 48%, respectively. When tests are conducted, considering future design variables, such as temperature, humidity, and out time, the results can be utilized to predict the long-term performance of tow prepreg and optimize composite manufacturing processes.