No abstract

According to the recent literature, the intensity of linear elastic residual stress\ud fields near the toe region of a welded joint can be quantified by the residual\ud notch stress intensity factors (R‐NSIFs). The computational effort required to\ud compute the R‐NSIFs implies strong limitations of applicability in practice,\ud owing to the very refined meshes needed and to the non‐linear transient nature\ud of welding process simulations, especially in 3‐dimensional numerical models\ud of large structures. The peak stress method (PSM) is a design approach that\ud takes care of the industrial needs of rapidity and ease of use. According to the\ud PSM, it is possible to evaluate the R‐NSIFs by using the peak stress calculated\ud at the point of singularity with coarse finite element (FE) models. While the\ud PSM was originally calibrated by using the Ansys FE code, in the present contribution,\ud the PSM has been calibrated to rapidly estimate the R‐NSIFs in the\ud Sysweld FE environment

In the high cycle fatigue (HCF) regime, the fatigue strength of welded joints is influenced by residual stresses (RS) induced during welding processes. If the weld toe is modelled via a sharp V-notch, the distribution of weld toe residual stress can be shown to be asymptotic with a singularity which follows either the linear-elastic or elastic-plastic solution depending on parameters that range across material properties, specimen clamping conditions, and the welding process. For thicker plates, multipass welding is used instead of single-pass welding to reduce the heat input and hence the width of the fusion zone (FZ) and heat-affected zone (HAZ). However, for a fixed plate thickness, the magnitude and extent of residual stresses near the weld toe will vary according to the number of passes used in the welding operation. In this paper the influence of multipass welding on the residual stress field near the weld toe has been analysed using a combination of analytical and numerical techniques. It was found that the higher the number of weld passes, the higher the magnitude of the residual asymptotic stress field near the weld toe

No abstract

The fatigue strength of ferritic, pearlitic, and solution strengthened ferritic ductile irons taken from heavy sections and characterized by long solidification times has been assessed. Starting from the idea of Murakami and co‐workers, a new model for the prediction of the fatigue strength is proposed. It allows a sound fatigue assessment of the fatigue strength of as‐cast ductile irons containing solidification defects, such as low nodule count, exploded, chunky and spiky graphite, or microshrinkage porosities. The newly developed equation validated by means of an extensive benchmarking with data taken from the literature has shown a very high potential for applications to thick‐walled components.