Analysis of weld root fatigue cracking in load-carrying high-strength aluminum alloy cruciform joints

This paper presents both experimental and analytical investigations into weld root cracking behaviors in load-carrying high-strength aluminum alloy cruciform joints. In test specimen preparations, electric spark machining was used to ensure weld penetration consistency. An analytical weld throat stress model is proposed for determining the maximum opening stress state and its weld throat angle. Its lower-order form expressed in terms of nominal stress is also proven to be adequate for interpreting the test data, which offers simplicity for practical applications. Comparisons between the lower-order weld throat stress and "engineering shear stress" used in some Codes and Standards are also discussed.