炭素繊維/エポキシ複合材の混合モード層間破壊特性に及ぼすひずみ速度およびモード比の影響

概要

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The interlaminar fracture toughness of carbon-fiber/epoxy composite laminates was investigated over wide ranges of loading rate, G=(10)^<-1>∿(10)^7J/m^2/s, and mode ratio, G_<II>/G_I=0∿∞, to study the effects of strain rate and mode mixture on micro- and macro-scopic fracture behavior. The MMF (Mixed Mode Flexure) and MMB (Mixed Mode Bending) specimens were employed to determine the mixed mode fracture toughness. The mode I, mode II and their mixed mode fracture toughness, G_<IC>, G_<IIC>, G_c, at the onset of crack growth was dependent on strain rate regardless of mode ratio; the fracture toughness at impact strain rate was about 10∿32% lower than the local maximum value at static strain rate. The mixed mode fracture toughness, G_c, obeyed the linear fracture criterion except for the region of low mode ratio, G_<II>/G_I≤3,and high strain rate, G≥(10)^2J/m^2/s. The microscopic fracture morphology was mainly dominated by the debonding of fiber/matrix interface at lower strain rate, whereas it was dominated by the cohesive fracture of matrix resin at higher strain rate.
社団法人日本機械学会の論文
2001-11-25