SHPB法を用いたENF試験によるCFRPの動的層間破壊じん性評価法の検討

概要

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To obtain the dynamic Mode II interlaminar fracture toughness of CFRP under impact loading,an impact bend test using split Hopkinson pressure bar (SHPB) method was apploed to the end notched flexure (ENF) specimen,and the estimation of G_II was investigated.The dynamic behavior of the ENF specimen during impact bending was analysed by the finite element method,and the history of the energy release rate G_II of the specimen was calculated using the crack-closure method.The energy release rae G^<cc>_II calculated by the crack-closure method was compared with the energy release rate G^<st>_II estimated by the formula for the static ENF test and load history of the output bar of SHPB.The results obrained are as follows.For the step input loading,the ratio G^<st>_II/G^<cc>_II oscillates strongly around unity and the oscillation continues after considerably long time,while for the ramp input loading with a finite rese-time,the oscillation is damped more quickly and the ratio G^<st>_II/G^<cc>_II approaches to unity more gradually as the rise-time increases.Therefore,the dynamic Mode II fracture toughness can be estimated by the formula for the static ENF test if the remp input loading were with an apropriate rise time is applied.
社団法人日本材料学会の論文
1993-12-15