炭素繊維強化エポキシ積層板の層間および層内混合モードI+IIき裂の進展挙動

概要

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Mixed-mode I+II fracture toughness of unidirectional graphite/epoxy laminates, T800H/# 3631. was studied. Mixed-mode propagation of interlaminar cracks was examined by mixed-mode bending tests where crack growth was stabilized by the coordinate conversion control method. Intralaminar fracture toughness was measured by tension tests of off-axis laminates with an inclined crack-like notch. The value of interlaminar fracture toughness increased with crack extension for G_I/G_<II>≤1.37 because of development of fiber bridging, while was nearly constant during crack growth for G_I/G_<II>≥0.57. There was no big difference between the interlaminar and intralaminar fracture conditions in the range of the mixed-mode ratio of G_I/G_<II>≤0.11. For G_I/G_<II>≤0.57,the mode I component of mixed-mode fracture toughness, G_I, was insensitive to the mode II component, G_<II>. while for G_I/G_<II>≤0.57,the G_I value decreased to zero as the G_I/G_<II> ratio decreased. A new criterion for the mixed-mode fracture condition was proposed, showing a good fit to the experimental results.
一般社団法人日本機械学会の論文
1999-07-25