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Poster

WEB Analysis of prospective SIF of 2D rough surfaces

Wednesday (27.05.2020)
14:45 - 14:50 Room 1
Part of:


Fatigue properties of parts built with Additive Manufacturing (AM) are strictly related to the process-induced defects' morphology and location: super cial or sub-surface defects are more detrimental for the fatigue behaviour than internal defects, due to a larger Stress Intensity Factor (SIF, representing the local stress state at a crack tip) that is the crack-driving force for a prospective crack. Several studies proved that surface valleys act as crack initiation sites [1],[2],[3],[4] similarly to surface micro-notches. The aim of this study is to nd a correlation between surface quality parameters and the fatigue behaviour of L-PBF AlSi10Mg specimens in "as-built" conditions. In details, CT scans are adopted to characterize surface quality and 2D Finite Element Analysis (FEA) is adopted to calculate the local stress distribution (SIF) at the cracks' tip in correspondence of the most critical valleys the surface pro le of some 2D slices extracted from two CT- scanned specimens. Murakami's approach [3] is followed to understand how the presence of di erent notches with similar depth on a certain surface region a ects the SIF in terms of shielding, expecting that the closer the notches are to each other, the more the SIF is decreased.

 

References
[1] D. Greitemeier, C. Dalle Donne, F. Syassen, J. Eu nger, and T. Melz. E ect of surface roughness on fatigue performance of additive manufactured Ti{6Al{4V. Materials Science and Technology (United Kingdom), 32(7):629{634, 2016.
[2] R. Molaei, A. Fatemi, N. Sanaei, J. Pegues, N. Shamsaei, S. Shao, P. Li, D. H. Warner, and N. Phan. Fatigue of additive manufactured Ti-6Al-4V, Part II: The relationship between microstructure, material cyclic properties, and component performance. International Journal of Fatigue, 132(October), 2020.
[3] Yukitaka Murakami. E ect of Surface Roughness on Fatigue Strength. Metal Fatigue, pages 305{320, 2002.

Speaker:
Lucia Barricelli
Politecnico di Milano
Additional Authors:
  • Prof. Dr. Stefano Beretta
    Politecnico di Milano

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