Remarks on quasi-static and interlaminar fracture toughness tests of composite structures

The critical energy release rate is one of the most important material properties used in fracture mechanics calculations, in particular, an estimation of a structural residual life. The determination of this material property can be performed in numerous standardized tests, depending on the desired crack extension mode. However, some parameters of such tests are not discussed in standards and are not taken into consideration during the determination of the critical energy release rate. In this study, the authors present results of their experimental studies for quasi-static and fracture tests on double cantilever beam specimens made of glass and carbon reinforced polymeric composite structures. The results of these studies show the influence of technological aspects of the specimens' preparation as well as data acquisition during performing experiments on the final results. These results will be used for a developed reversed numerical model for a prediction of the residual life of composite structures containing barely visible impact damage.