In this study, an epoxy insulation barrier for high voltage GIS was developed using epoxy and a filler with a Young`s modulus of 11 GPa. The material was investigated using a simulation of the principal stress, displacement, and safety factors while optimizing the profile shape. The simulation showed that thelarger Young`s modulus of the Al₂O₃ filler compared to the SiO₂ in the epoxy insulation can contribute to an increase in resistance to mechanical fracturing for theoptimized profile barrier in high voltage GIS. In addition, the safety factor was improved by 10%. It can be concluded that the mechanical fracturing properties of the insulation barrier can be enhanced by increasing the content of the elastic filler, Al₂O₃, for high voltage GIS applications.