Sensitivity analysis of fracture behavior in carbon-epoxy composite at different displacement rates under mode I tensile loading by regression analysis

In this article, the sensitivity analysis of the displacement rate effect under tensile loading on the crack growth behavior in the carbon-epoxy composite has been investigated. For this objective, the tensile test was performed on double cantilever beam samples, according to the ASTM-D5528 standard under displacement-controlled loading and under displacement rates of 0.05, 0.5, 5 and 50 mm/min. Then, the regression analysis was done on outputs of experimental data by the Minitab software. For this objective, the sensitivity analysis was performed on three fracture characteristics of composite specimens. These fracture mechanics parameters were the critical energy release rate (with three different fracture energy methods), the maximum failure force and the initial crack tip opening displacement by the use of the digital image correlation technique. Results showed that the variation of the displacement rate affected the maximum failure force and the energy release rate and therefore, these values were sensitive to changes in the displacement rate. However, the maximum value of the initial crack tip opening displacement of the composite was dependent on the logarithmic displacement rate under tensile loading. Finally, the changing trend of fracture mechanics characteristics in the composite was increasing by increasing the displacement rate.