Experimental investigation of CFRP fracture toughness by delamination type

The results of analyzing fracture toughness in carbon fiber-reinforced plastics by the type of delamination are presented in the article. The goal of this paper is investigation of delamination propagation process and fracture mechanics parameters in modern CFRPs. This type of composite materials is extensively used in high load aerospace structures. Modern polymer composite materials are the subject of our research. A technique of manufacturing specimens for testing by the vacuum infusion process is presented in the paper. Experimental investigation of delamination propagation process by mode I and II was performed with the aid of up-to-date testing equipment using a special type of specimens such as a double cantilever beam. Researchers usually use this type of specimen for the validation of their numerical models. Critical values of energy release rate and load-displacement curves were obtained for two types of material – unidirectional and woven. Examination of microscopic sections of the tested specimens using an optical microscope allowed us to identify the specific fracture mechanisms of material structure.