This document discusses the non-linear finite element analysis of a flywheel made of different materials. It begins with an introduction to flywheels and the motivation for performing non-linear analysis. The flywheel model is created in SolidWorks and meshed. Non-linear static analysis is performed in ANSYS considering step loading and centrifugal forces. Various parameters like deformation, stress, and factor of safety are analyzed and compared for aluminum alloy and cast iron flywheel models. Shape optimization is also performed to reduce the flywheel mass by 20%. Experimental validation of deflection values matches well with FEA results, with error within 3-4%. Aluminum alloy is found to have lower stresses compared to cast iron, making it better