J0450201 CFRP積層板の粘塑性挙動のモデル化

Abstract

We estimate effects of ply thickness on mechanical properties and damage evolution of CFRP angle-ply laminates under various tensile loading. It should be noted that the laminate thickness is almost the same, but the ply thickness are quite different. Monotonic tensile tests, cyclic loading-unloading tensile tests and stress relaxation tensile tests are performed on [(±θ)_<12>]_s (t-0.05 prepreg×48plies, t-0.05 ply thickness), [(±θ)_4]_s (t-0.15 prepreg×16plies, t-0.15 ply thickness) and [(+θ)_4/(-θ)_4]_s (t-0.15prepreg× 16plies, t-0.6 ply thickness) T700SC/2500 carbon/epoxy laminates with various fiber directions (θ=30, 40, 45, 50 and 67.5°) at 1.0 mm/min crosshead speed. Laminates with thin ply thickness showed high strength and fracture strain. From SEM observation, t-0.6 laminates exhibit brittle fracture, however delamination occurred in each interlaminar interface in thin ply thickness (t-0.05, t-0.15) laminates. In stress relaxation tests, laminates exhibit nonlinear response and then stress relaxation behavior appears. In addition, it is considered that each angle-ply laminate have rate dependence in comparison with monotonic tensile test results at 0.1mm/min crosshead speed. Also damage evolution can be determined by cyclic loading-unloading tensile tests. We use mesoscale damage model to investigate damage evolution in CFRP laminates. From damage observation and damage evolution analysis, it is considered that thin ply thickness laminate can accumulate damage in specimen until high stress state.