The mechanical properties of discontinuous carbon fiber-reinforced plastics (CFRTP) were evaluated in this study using a multiscale numerical analysis method. The internal structures of the discontinuous CFRTP were classified into three scales: macro-, meso-, and microscale, based on X-ray CT observation and image analyses. Subsequently, finite element models were prepared while considering the characteristic internal structures in each scale. Using these models, numerical simulations (based on the homogenization method) were performed in sequence to identify the constitutive equations regarding the homogenized materials in the micro- and mesoscales. The numerical simulation (also based on the finite element method) was performed, and the elasto-viscoplastic properties of the discontinuous CFRTP were evaluated. The stress-strain curve obtained from the multiscale numerical analysis method agreed well with the experimental result of the uniaxial tensile test in both elastic and viscoplastic regions. In addition, the strain distributions showed a similar tendency between the numerical and experimental results. These results validated the proposed multiscale numerical analysis method.
