Authors: C Vidal V Infante
Publish Date: 2014/01/29
Volume: 23, Issue: 4, Pages: 1340-1349
Abstract
Fatigue is undoubtedly the most important design criterion in aeronautic structures Although friction stirwelded joints are characterized by a high mechanical performance they can enclose some defects especially in their root These defects along with the relatively low residual stresses of the friction stirwelding thermomechanical cycle can turn into primary sources of crack initiation In this context this article deals with the fatigue behavior of friction stirwelded joints subjected to surface smoothing by grinding improvement technique The 4mmthick aluminum alloy 2024T351 was used in this study The fatigue strength of the base material joints in the aswelded condition and the sound and defective friction stirwelded joints improved by grinding were investigated in detail The tests were carried out with a constant amplitude loading and with a stress ratio of R = 0 The fatigue results show that an improvement in fatigue behavior was obtained in the joints repaired by superficial grinding technique The weld grinding technique is better especially for lower loads and increases the high cycle fatigue strength The fatigue strength of the improved welded joints was higher than that of the base materialThe authors would like to acknowledge the financial support from the Portuguese Foundation for the Science and Technology FCT through the PhD scholarship FCT SFRH/BD/62963/2009 and the material supplied by the OGMA – Indústria Aeronáutica de Portugal SA a specialist aviation company since 1918
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