Fatigue life improvement for aeroengine disks based on active thermal management

Fatigue life is closely associated with stress level for aeroengine disks. A stress control method using active thermal management has been proposed and may benefit fatigue life. This study numerically investigates the effect of active thermal management on fatigue life of disks and explores possible methods for fatigue life improvement. In this numerical modeling investigation, a disk of uniform thickness containing a preset initial crack subjected to simplified loads is considered. Active thermal management is conducted by transferring parts of the rim's heat flow to actively heat the hub, and this process is represented by energy transfer coefficient φ. A numerical simulation is used to compute the temperature and stress distributions of the disk, and the fatigue life is analyzed using universal weight function expressions. The results show that the fatigue life under an actively managed thermal load (φ = 0.10) increases by 26.1% compared with that of the conventional load (φ = 0). Thus, active thermal management can be used to increase the fatigue life of a disk. The reason for this improvement in fatigue life is studied numerically and theoretically. The temperature becomes a V-shaped distribution as the hub is heated, and the thermal stresses that are induced by reverse temperature gradients counteract parts of the centrifugal stresses; the reduced stress enhances fatigue life.