Parametric and non-parametric tests for the evaluation of interlaminar fracture toughness of polymer composites

This study is based on the statistical analysis of interlaminar fracture toughness of various laminated polymer composites used in aerospace applications through parametric and non-parametric tests. Tukey's, Dunkan's, two-sample t-test, and Kolmogorov-Smirnov tests are used to analyze tensile mode interlaminar fracture toughness of various fiber-reinforced polymer composites obtained by beam theory, modified beam theory, and modified compliance calibration method. Among the studied composite samples, modified compliance calibration method provided the highest average interlaminar fracture toughness, whereas the modified beam theory showed the lowest one. Room temperature cured carbon fiber-reinforced composite samples exhibited higher interlaminar fracture toughness than the autoclave cured samples. Two-sample t-test show that all methods are found coherent with each other in terms of being significantly different. On the contrary, Kolmogorov-Smirnov test revealed no significant difference. Besides, Tukey's and Duncan's tests exhibited almost the same results in regard to significant differences except those obtained by the modified compliance calibration method. Two-sample t-test method should have to be performed in order to observe significant relations rather than Kolmogorov-Smirnov test, since the results of Tukey's and Duncan's tests are only consistent with each other for the beam theory and modified beam theory method.