Abstract
Directional variations of viscoelastic properties of CFRP (carbon fiber reinforced plastic) were examined in terms of the complex compliances and the viscoelastic models determined through impact tests on two types of CFRP rods, which were made from the same prepreg but in different fiber orientations. The coordinate transformation law of elastic constants in anisotropic solids was modified to treat the present viscoelastic case by substituting viscoelastic functions for corresponding elastic constants. According to this procedure, experimental data of viscoelastic properties obtained from impact tests were evaluated. The results revealed that the substitution procedure on the transformation law would provide a reasonable estimation of viscoelastic properties in arbitrary direction.
