The damage tolerant shaft and associated method of fabricating a damage tolerant
shaft provide a drive shaft that is tolerant of accidental and projectile damage
to a portion of the drive shaft. The damage tolerant drive shaft is designed with
internal ribs or lobes, such that a closed portion of the drive shaft will likely
remain after the drive shaft is partially damaged. Thus, the damage tolerant drive
shaft is able to continue proper operation after being partially damaged because
the closed portion of the shaft creates a closed path around which the internal
shear stresses that correspond to the required torque loads flow. In addition,
the damage tolerant shaft and associated method provide damage tolerance without
increasing the radius, wall thickness and/or weight of the drive shaft.
