C211002 Analyzing the Hub Fatigue Accident of Mitsubishi Motors and Yurikamome Line using Learning from Failures

Abstract

In 2004, Mitsubishi Motors Corporation recalled the D-type hub of a front shaft of a large-sized truck due to fatigue. The managers of the Mitsubishi were indicted for too late execution of the recall without any scientific discussion on the fatigue mechanism. The paper presumes the fatigue mechanism using the similar accident of a hub/wheel in the new transit Yurikamome. The hubs have a vibration due to positive camber angle; the vibration induces a wear between the hub/wheel: the wear makes a deformation of the worn flange part of the hub/wheel; a hub bolt tightly fastens the wheel/hub with slightly titled posture; a small radius corner has an excess tensile stress; the stress makes crack propagation. The failure scenario of the Mitsubishi hub accident should be similar to that of the Yurikamome hub.