The effect of stress ratio on the fatigue behavior of additively manufactured porous biomaterials

Master thesis (2016)

Authors

Contributors

A.A. Zadpoor (mentor)
C.D. Rans (mentor)
Programme
Materials Engineering and Applications (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2016 De Krijger, J.
Titanium Fatigue Biomaterials Stress ratio
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Published Date

08-03-2016

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Programme

Materials Engineering and Applications

Abstract

Meta-biomaterials are porous biomaterials created by additive manufacturing techniques such as Selective Laser Melting. These materials are built up form a repeating unit cell, resulting in a porous structure that can be applied for bone implants or prosthetics. The mechanical properties of these meta-biomaterials can be tailored by variations in unit cell type and strut thickness, resulting in different porosity values. This makes it possible to create a material with mechanical properties similar to bone, which prevents negative side effects of conventional bone implants such as stress shielding. The fatigue behavior of these meta-biomaterials has been studied before, but only at a single stress ratio of R=0.1 This study investigates the fatigue behavior at different stress ratios which result in an increased mean stress. A cylindrical porous structure that is built up from a diamond unit cell is tested at stress ratios of R=0.1, R=0.3, R=0.5, R=0.7 and R=0.8. Two samples types are made of Ti-6Al-4V ELI powder, resulting in a theoretical porosity of 80% and 10%. Also an experimental DIC method is developed, to visualize the deformation behavior during the fatigue tests.