University of Michigan

American Axle & Manufacturing, Inc.

Jifa Mei

Pingsha Dong

Xianjun Pei

Chih-Hung Chung

Anoop Vasu

Ravi S Desai

Shizhu Xing

A weldment includes a first component, a second component, and a weld joint coupling the first and second components together. The weld joint forms a heat affected zone in the first component and creates residual tensile stress in the first component. The first and second components cooperate to define a pocket configured to position a highest magnitude of the residual tensile stress in the first component in a location that is outside of the heat affected zone of the first component.

Vehicle driveline component with weldment having air pocket configured to shift residual stress in weldment away from the weld joint

Due to geometric discontinuities introduced by welding and joining processes, stresses or strain cannot be calculated reliably calculated using modern analytical and computer methods as result of stress or strain singularity at joint locations, which leads to severe mesh sensitivity. Design and fatigue evaluation of these structures remain empirical. This disclosure addresses mesh insensitivity of stress/strain calculations for welded structures through a cut-plane traction stress method through a novel post processing of conventional finite element computation results, as well as provides a unified fatigue evaluation procedure for fatigue design and structural life evaluation for both low-cycle and high cycle fatigue regime subjected to either proportional or non-proportional multiaxial fatigue loading, as well as a simple and reliable method for treating spot welds.

Unified fatigue life evaluation method for welded structures

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Ann Arbor, MI, United States of America

Jifa Mei