Optimum design of hybrid and non-hybrid laminated composite materials using GA/GPSA algorithm for high dimensional stability

In the last few decades, composite materials are increasingly used worldwide in place of traditional materials in industrial applications such as aerospace, defense and automotive. Dimensionally stable composite materials that can resist sudden temperature changes are needed, especially in aerospace applications. Fiber-reinforced laminated composite materials have a good potential to meet the dimensional stability needs of space structures thanks to their tailorability properties. In this thesis, it is aimed to obtain the highest dimensional stability against temperature changes in fiber reinforced laminated composite plates. For this purpose, firstly, stacking sequence optimization was performed using both continuous and conventional angles to obtain the lowest thermal expansion coefficients of symmetrical and balanced carbon/epoxy composite plates under high modulus of elasticity constraints, and the thermal resistance of the selected optimum designs was tested. Secondly, using eight different composite materials (Aramid/Epoxy, AS4/Epoxy, Boron/Epoxy, E-Glass/Epoxy, IM6/Epoxy, GY70/Epoxy, Kevlar49/Epoxy and Spectra/Epoxy) hybrid composite plates with optimum continuous and conventional stacking sequences giving the lowest coefficients of thermal expansion were investigated in two different sequences including two materials and the thermal resistance of the selected hybrid designs was tested. The GA/GPSA hybrid algorithm constituted with the optimization toolbox in the MATLAB program was used as the optimization algorithm for both studies. The results are presented together with the results of non-hybrid optimization study of the composite materials used. The results reveal that better dimensional stability can be obtained by hybridizing composite materials than non-hybrid materials.