Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Arjunan, Arun, Demetriou, Marios, Baroutaji, Ahmad and Wang, Chang (2019) Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds. Journal of the Mechanical Behavior of Biomedical Materials. p. 103517. ISSN 1751-6161

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Abstract

Critically engineered stiffness and strength of a scaffold are crucial for managing maladapted stress concentration and reducing stress shielding. At the same time, suitable porosity and permeability are key to facilitate biological activities associated with bone growth and nutrient delivery. A systematic balance of all these parameters are required for the development of an effective bone scaffold. Traditionally, the approach has been to study each of these parameters in isolation without considering their interdependence to achieve specific properties at a certain porosity. The purpose of this study is to undertake a holistic investigation considering the stiffness, strength, permeability, and stress concentration of six scaffold architectures featuring a 68.46–90.98% porosity. With an initial target of a tibial host segment, the permeability was characterised using Computational Fluid Dynamics (CFD) in conjunction with Darcy's law. Following this, Ashby's criterion, experimental tests, and Finite Element Method (FEM) were employed to study the mechanical behaviour and their interdependencies under uniaxial compression. The FE model was validated and further extended to study the influence of stress concentration on both the stiffness and strength of the scaffolds. The results showed that the pore shape can influence permeability, stiffness, strength, and the stress concentration factor of Ti6Al4V bone scaffolds. Furthermore, the numerical results demonstrate the effect to which structural performance of highly porous scaffolds deviate, as a result of the Selective Laser Melting (SLM) process. In addition, the study demonstrates that stiffness and strength of bone scaffold at a targeted porosity is linked to the pore shape and the associated stress concentration allowing to exploit the design freedom associated with SLM.

Item Type: Article
Keywords: Additive manufacturing, Titanium bone scaffold, Permeability, Stiffness, Strength, Porosity
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Dynamics, Control and Vehicle Research Group
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA0174 Engineering design
T Technology > TA Engineering (General). Civil engineering (General) > TA0349 Mechanics of engineering. Applied mechanics
Depositing User: Chang Wang
Date Deposited: 11 Nov 2019 09:49
Last Modified: 18 Nov 2019 08:00
URI: http://sro.sussex.ac.uk/id/eprint/87904

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