Abstract: Through adopting the pre-stressed structure, the stress and displacement distribution of composite material flywheel can be improved to certain extent, thereby increasing the energy storage density of flywheel. Considering characteristic of composite material and pre-stress structure, a calculation model is established on the basis of anisotropy symmetric theory. The analytic formulas of stress and displacement calculation of composite material energy storage flywheel with two-layer pre-stressed rotor structure under working speed are obtained. The radial, circumferential stress and radial displacement at a random point of inner and outer layer of flywheels are analyzed completely. Moreover, with the established model, the effect of different position of flywheel on radial, circumferential stress and radial displacement under any rotational speed are investigated. The results indicate that for inner rotor, the maximal radial stress occurs at exterior margin of the flywheel, the maximal circumferential occurs at inner margin. For outer rotor, the maximal radial and circumferential all occur at inner margin. When the angular velocity  increases from 0 to 5 000 rad•s−1, the radial stress, circumferential stress and radial displacement also increase. When =600 rad•s−1, the maximal radial, circumferential stress and radial displacement also occur at r=0.27 m, which is between the contact surface of two-layer rotor. It provides an important reference for flywheel design.

Key words: Stress and displacement distribution, Analytic method, Composite material energy storage flywheel, Pre-stressed rotor structure, Simulation calculation