Statistical methods in the analysis of strength parameters of epoxy-glass composites modified with rubber recyclate

Abstract

The article presents a statistical analysis of strength parameters of newly developed epoxy-glass composite materials modified with the addition of rubber recyclate.Three variants of materials with a percentage of recyclate content in the composite matrix of 3%, 5%, 7% and a reference variant without the addition of recyclate were used for the study. The samples were subjected to an impact test on a ZWICK RKP 450IR-GE impact hammer. Resilience measurement values were subjected to statistical analyses at the significance level = 95%, such as: testing the normality of distributions with the Shapiro-Wilk test, testing differences between pairs with the Student's t-test for dependent groups, and testing ANOVA differences for independent groups.The Shapiro-Wilk test confirmed that the resilience variables for all tested samples were in normal distributions; therefore the highest power parametric tests were used to test the differences. Using the Student's t-test, it was confirmed that between pairs of variables in configurations: standard sample with the modified sample, there were significant statistical differences in the distribution of resilience values for all samples. ANOVA confirmed significant changes in impact strength in 10 comparison variants.The obtained test results showed that in 9 compared cases, there were significant statistical differences, and in one case, there were no significant differences.The performed statistical analyses confirmed their significant usefulness in the process of qualification of strength parameters for materials with high anisotropy, such as composites.The manufactured products are innovative in terms of the method of using the addition of rubber recyclate as a filler for epoxy-glass composites. The use of static methods for their study also has practical value. It optimizes the analysis methods of the results of measurements of strength parameters of new composite materials.