Using response surface methodology for modeling and optimizing tensile and impact strength properties of fiber orientated quaternary hybrid nano composite

Abstract

In current study, weight percentage of nano silica and nano clay and also fiber orientation have been chosen as independent variables and the affect of these variables on tensile and izod impact strength of epoxy/glass fiber/SiO2/clay hybrid laminate composite has been investigated. Central composite design (CCD) which is subset of response surface methodology has been employed to present mathematical models as function of physical factors to predict tensile and impact behavior of new mentioned hybrid nano composite and also optimizing mentioned mechanical properties. Totally 20 experiments were designed with 6 replicates at center point. The maximum and minimum value of tensile strength were 450.90MPa and 158.16MPa which occurred in design levels 1 and 14 respectively, also the maximum and minimum of izod impact strength were 10.47kJ/m2 and 2.56kJ/m2 which occurred in design levels 13 and 14 respectively. The optimization results using optimization part of Minitab software showed that the best tensile strength was obtained 488.53MPa and occurred in 3.5wt% of nano silica, 1.1wt% of nano clay and 9° of fiber orientation and after preparing and testing five samples average value of tensile strength was obtained about 480MPa. Also the results showed that the best impact strength obtained from software was 11.35kJ/m2 and occurred in 4.03wt% of nano clay, 5wt% of nano silica and 0° of fiber orientation. The optimization results also showed that tensile and impact strength at optimum values improved up to 6.4% and 203.5% compared to level 1 and 14 and 6.02% and 303.6% compared to level 13 and 14 respectively. In addition, the fracture surface morphologies of the quaternary nano composites were investigated by scanning electron microscopy (SEM).