A number of different joining processes (spot welding, arc welding, laser welding, and adhesive bonding) were used to fabricate tubular T-joints with the objective of finding the process which would give the best fatigue performance in both out-of-plane and in-plane loading conditions. Fatigue test results led to a development of an empirical model for prediction of fatigue behaviour of these joints. An application of the local approach models did not give accurate results, since during cycling of the T-joint, more than one fatigue crack always initiated. A global approach was used assuming that any fatigue crack initiation and propagation would be represented by joint's flexibility change. Initial flexibility(f_i) and rate of flexibility increase (df/dN) were determined experimentally for each type of joint tested. Distortion energy factor (triangle openGAMMA), geometry coefficient (alpha), and initial energy range (triangle openU) were also determined. This paper will present both experimental data and predictions made using this proposed model, which correlated well for joints tested.
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