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摘要
The constant-amplitude fatigue test of resistance spot welded tension-shear joints of magnesium alloy AZ31B/titanium alloy TA15 dissimilar materials was carried out, and the fatigue fracture characteristics were observed by scanning electron microscopy. It is observed that there are two failure modes under different load levels. Based on the experimental results, a finite element model was established for the spot welding specimen, and the elastic-plastic stress-strain near the spot welded joints was analyzed. Then the notch stress method and local stress-strain method were used to predict the fatigue life of the spot welded joints and the predicted results were compared with the experimental life, and the relevant data in other papers were also discussed. The results of finite element analysis and fatigue life prediction show that the stress and strain concentration are mainly located on the magnesium alloy side of the notch root around the weld nugget; the electrode indentation depth on the specimen surface has little effect on the fatigue prediction results. The fatigue life predicted by notch stress method is relatively conservative compared with the experimental life. The two damage prediction results of the local stress-strain method show that the Smith-Watson-Topper (SWT) method is more reasonable than Manson-Coffin (MC) method. ? 2022, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.
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