Mixed-Mode Fracture Test of CFRP Laminates

抄録

Mixed-mode (mode I and mode II) interlaminar fracture toughness of uni-directional reinforced and woven carbon fiber-reinforced plastic (CFRP) is evaluated using DCB specimens. A new testing apparatus is made in order to change the ratio of mode I to mode II across a wide range. The fracture toughness value is evaluated based on beam theory, and the deformation of the specimen is analyzed by the finite element method (FEM) . The relationship between compliance and crack length obtained in the experiment agrees with the results obtained by FEM. The constant fracture toughness value, G_c, which is independent of crack length, is obtained. Due to the decrease of the G_I/G_II ratio, the fracture toughness value increases. It is shown that the role of mode II changes largely due to the change in the ratio of mode I to mode II, though the mode I component maintains a nearly constant value.