Investigation on Metal-Composite Hybrid Flywheels using Finite Element Method

Abstract

This research is aimed to investigate the kinetic energy storage of a hybrid metal-composite flywheel rotating at high speeds. The upper limit of energy, which flywheel can supply, is restricted by the strength of material because both energy and stress are proportional to the density of the material and the square of the velocity. Metal flywheels operate at lower rotational speed and supply less energy than the composite flywheels. Composite flywheels have a very high density per unit mass, but lower energy density per unit of the design volume. The ultra-high speed of composite flywheels creates some engineering challenges such as the necessity to operate in a vacuumed case and use of electromagnetic bearings. Combined metal-composite flywheel might be a reasonable compromised solution. The main task is to find proper ratio of constituents and their architecture. This is the primary task of the Thesis work. However, composite flywheels are suffering cost-per-unit compared to metal flywheels. Therefore, in this paper, the researcher will focus on the potential of hybrid metal-composite flywheel by optimizing the safety factor. The goal of the safety factor is to acquire similar minimum values of each component of the designated model. In the first part of the thesis, the content will be focusing on the analytical solution of flywheel ring. In the second part of the paper, the FEM simulated model will be discussed. Each section will be shown the energy storage of the rotating model, the stress analysis and comparison between models.