62 - Numerical investigation of the influence of defects on the multiaxial fatigue strength of additively manufactured alloys
Abstract
Whether it’s automotive, bio-mechanics or aeronautical industry, additive manufacturing (AM) is already in reality due to its wide range of advantages. However, limitations, like the presence of defects induced by the fabrication process that depends on the input process parameters, continue to be a crucial issue for the design of industrial components regarding fatigue damage. The present work aims to use numerical simulation to study and understand the impact of typical AM defects, especially the lack-of-fusion (LoF)/complex-shaped defects, on the multiaxial fatigue behaviour of high-strength materials. The stress and strain distributions around any defect depend on its size, position with respect to the free surface, and morphology. In addition, studies have shown that conservative fatigue strength predictions are usually obtained when the stress gradients near the defects are not accounted for [F. Morel et al., International Journal of Fatigue, 2009; A. Karolczuk et al., Computational Materials Science, 2008; Y. Nadot & T. Billaudeau, Engineering Fracture Mechanics, 2006]. In the current study, a model is proposed based on the Crossland multiaxial fatigue criterion, involving a non-local analysis of the calculated stress and strain fields to assess the fatigue strength. Calibration of the non-local parameter is achieved by comparing the numerical predictions to experimental results. The model is then applied to consider the criticality in fatigue of real defect geometries, such as gas pores and complex-shaped defects that were induced during the fabrication of Ti64 using a laser powder bed fusion (L-PBF) process. In particular, the fatigue strength anisotropy is assessed for these two defect populations.
Speaker
Sai Sreenivas Penkulinti
Discover speaker profileI2M Bordeaux, ENSAM, Bordeaux, France
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62 - Numerical investigation of the influence of defects on the multiaxial fatigue strength of additively manufactured alloys
Date/Time
20/03/2024
11:55 am -12:15 pm
Location
Room 7