Fatigue Design Diagram for Weld Joints on Aluminum Alloy Carbody Shells

Abstract

In order to develop some fatigue design diagrams, the authors carried out weld joint fatigue tests for an aluminum alloy carbody shell. The hollow extrusion weld joints of a doubled-skinned shell and two types of reinforced weld joints of a single-skinned shell were selected as being representative of carbody shell weld joints. The authors created a fatigue design diagram for the hollow extrusion weld joints by means of a statistical treatment of an S-N curve obtained from the fatigue tests using both small-size and full-scale test specimens. In addition, they used the full-scale test specimens in the same manner to develop a common diagram for two kinds of reinforced welds used on single-skinned shells. The diagrams were valid for evaluating fatigue strength from the stress range of materials near the weld joints.