Three-dimensional similarity law for elastic wave propagation in CFRP with concentrically curved fibers

Abstract

The wave front of an elastic wave in carbon fiber reinforced plastic (CFRP) with curved fibers is distorted owing to the fiber curvature effect. The similarity law to estimate the two-dimensional (2D) elastic bulk wave behavior in CFRP with concentrically curved fibers was presented in our previous study. In this research, the three-dimensional (3D) propagation of bulk waves in CFRPs with concentrically curved fibers was examined. Using 3D-printed CFRP specimens, the 3D propagation behavior of the quasi-longitudinal wave emitted from the point source was visualized virtually. Considering these results, the similarity law was expanded to the case of the 3D propagation behaviors of the bulk waves. Mathematical discussion based on the governing equations shows that the expansion parameters need to be equal in both the thickness and the radial directions to satisfy the similarity law in the 3D case, in addition to the conditions required to satisfy the 2D similarity law. By conducting the experimental visualization, it was demonstrated that the shape changes of quasi-longitudinal waves follow the similarity law, which was eventually verified for 3D propagation.