Abstract
Keywords:
Fatigue, Structure, Evaluation, Welding, Fatigue Life, Spot Welded Structures, Nominal Structural Stress
Abstract
The nominal structural stress calculation method proposed by D. Radaj includes some problems as follows. (a) How the value of the diameter D is decided in the method? (b) It is not possible to estimate nominal structural stress of the spot welded joints that fatigue crack is generated in causing stress concentration around the nugget edge, even if no general loads affect the nugget. We proposed the new method that can accurately obtain nominal structural stress of the spot welding in order to solve above-mentioned problems. The proposed new method calculates the nominal structural stress through the circular plate theory in theory of elasticity. This theoretical analysis uses not only general loads but also node displacement around spot welding got in FE shell analysis as boundary condition. This new proposed nominal structural stress calculation can solve the above-mentioned problems (a) (b), and the solution accuracy was more improved. Fatigue test data could be arranged in a narrow bandwidth by the nominal structural stresses by proposed method, it was indicated that proposed method could estimate the fatigue life of spot welding. The proposed method is useful for the prior evaluation technique that can predict the fatigue life of spot welding by CAE.