A method of obtaining the anisotropic complex moduli of carbon fibers by fitting

A novel fitting method of obtaining the anisotropic complex moduli of fibers based on the complex moduli of matrix and composites is presented. The complex longitudinal, transverse and in-plane shear moduli of the unidirectional T700 carbon fiber reinforced epoxy resin composite and the complex modulus of its matrix are measured using dynamic mechanical analysis. The predicted properties of the composite are calculated using the generalized method of cells (GMC). The complex axial, transverse and axial shear moduli of the carbon fibers are obtained by minimizing the sum of the squares of the modules of the difference between the test properties and predicted properties. Finally, the results of the experiment, finite element analysis, and GMC are compared. The results show that the complex axial and transverse moduli of the carbon fibers can be accurately evaluated, while the complex axial shear modulus cannot be accurately determined.