Simulation on Kink-band Formation during Axial Compression of a Unidirectional Carbon Fiber Reinforced Plastic Constructed by X-ray Computed Tomography Images

X-ray computed tomography was used to obtain cross-sectional images of a unidirectional carbon fiber reinforced plastic,where fiber locations in each cross-sectional imagewere identified.Thethree-dimensionalmodelwith fiberwavinesswasdevelopedbyconnecting thefiber locations along the fiber direction. Numerical simulation for the initiation and formation of a kink-band during axial compression was performed using the three-dimensional finite element model.Theloadwasincreasedalmostlinearlyuntilitreachedthecompressivestrength,afterwhich both load and displacement were decreased, showing snap-back behavior. The matrix yielded locallywiththeincreasedaxialcompression,andfibersstartedtofallduetoinsufficientsupportby the yielded matrix.A kink-band was formed with an increase in the yielded area, and thus, the initiationofakink-bandwasdefinedasthelocalyielding ofthematrix.Itwasalsoshownthat the kink-bandwasformedat thelongitudinallocationatwhichtheaverageoflocalfibermisalignment angles in thecross-sectionwas relativelylarge.