Life fatigue estimation of welding seams based on notch strains

When based on structural stress acting on shell elements, the stress simulation for welding seams on thin sheets provides no sufficient correlation with damages occurring during real component tests under operational load. The calculation technique on hand is based on the analysis of the operational strength behavior of crucial positions such as toe notches and root notches. The notches are fictitiously rounded with radii of 0.05 mm. The notch root stress reduced by the support effect (especially the microstructural support effect) has proved to be an appropriate stress criterion. In order to verify the universality of the method for other welding seam geometries as well, the fatigue strength behavior of H-specimen was not only simulated for MAG-welding seams but also for laser welding seams and spot welding. The fatigue life estimation was carried out in accordance with the critical plane method and by using the PSWT–stress-cycle curve. The Miner rule was used as hypothesis of damage accumulation.