Delamination fracture toughness and failure mechanisms of carbon-fibre reinforced composite laminates: A review A review

A popular approach to the characterisation of the propagation of interlaminar cracks has been through the linear-elastic-fracture-mechanic (LEFM). The mechanical analysis and characterisation of the propagation of interlaminar cracks were mentioned in general. In a number of publications, the fracture behaviour of a carbon-fibre reinforced polymer composite was shown to be dominated by the properties of the polymer-matrix phase, affecting both the stability of crack propagation and magnitude of the measured fracture toughness. It is shown that for the interlaminar of some polymer/fibre composite the value of the interlaminar fracture energy generally increases as the crack propagates through the composite, i.e. arising 'R-curve' is observed. Thus, it is not usually possible to assign one unique value to the interlaminar fracture energy for any given mode of loading. The performance of the 'R-curve' is various for different mode of loading. In fact, the plastic deformation must more or less occur at the crack tip during crack propagation in polymer/fibre composite, if even thermosetting resin matrix which are some of the most brittle types of polymer. The common features observed were banding (microshear band) (in thermosetting) and crazing (in thermoplastic). The presence of plastic deformation in process of the interlaminar crack propagation under different mode loading affects the interlaminar failure mechanism pronouncedly. To sum up, the delamination failure mechanisms of the carbon-fibre reinforced composite laminates have two: (1) If interface adhesion between fibre and matrix is weak, the delamination failure mechanism is seem to be interface debonding with accompanied matrix failure, (2) if the interface adhesion between fibre and matrix is good, the delamination failure is commonly matrix failure. Finally, the Mixed-Mode delamination failure criterion and the concept of the interaction parameter were introduced. (orig./AKF)SIGLEAvailable from TIB Hannover: RN 4165(1994,40) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman