Mode II interlaminar fracture toughness of multidirectional carbon fiber reinforced plastics cracking on 0//0 interface by Raman spectroscopy

The Mode II fracture toughness of multidirectional carbon fiber reinforced plastics (CFRP) was investigated using end notched flexure (ENF) specimens and the Raman coating method. The ENF specimens were pretreated with thin films of PbO deposited on the surface by physical vapor deposition (PVD) to measure strain by Raman spectroscopy. The strain distributions near the crack tip of the CFRP were measured by Raman spectroscopy. The fracture toughness for multidirectional CFRP in Mode II was determined from these measured strains. The results coincided with those found using the conventional experimental method for ENF specimen and numerical analysis using the finite element method (FEM).