Examinando por Autor "Peach, Chris"

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Mechanical, biological and tribological behaviour of fixation plates 3D printed by electron beam and selective laser melting
(Springer Nature, 2020-07-06) Abdulaziz Al-Tamimi, Abdulsalam; Hernández, Miguel Á.; Omar, Abdalla; Morales-Aldana, David Felipe; Peach, Chris; Bartolo, Paulo
Commercially available fixation plates are built using metallic biocompatible materials such as titanium and its alloys and stainless steel. However, these plates show a stiffness mismatch comparing to bone, leading to stress shielding and bone loss. In this paper, we investigate the combined use of topology optimisation and additive manufacturing to print fixation plates with reduced stiffness and improved biological performance. Ti-6Al-4 V plates were topology optimised considering different loading conditions and volume reductions and printed using electron beam melting and selective laser melting. The effect of processing conditions on the mechanical properties, microhardness, wear resistance and surface roughness was analysed. Results show acceptable wear resistance values for a medical device and a reduction of stress shielding by increasing volume reduction. It is also shown that no polishing is required as 3D printed plates are able to support cell attachment and proliferation. In comparison to commercial plates, 3D printed ones show significantly better biological performance. For the same design, SLMplates present higher mechanical properties, while EBM plates present better cell attachment and proliferation.
Topology optimised metallic bone plates produced by electron beam melting: a mechanical and biological study
(Springer Nature, 2019-05-25) Abdulaziz Al-Tamimi, Abdulsalam; Huang, Boyang; Vyas, Cian; Hernández, Miguel Á.; Peach, Chris
Metallic bone plates are commonly used as a medical implant to treat bone fractures. The gold standard materials for these implants are biocompatible 316L stainless steel, cobalt chromium, titanium and its alloys (e.g. CoCrMo and Ti6Al4V). However, the main disadvantage of these implants is the material stiffness mismatch between the implant and bone. This mismatch may negatively affect the biological processes in bone healing. This paper investigates topology optimization to produce plates with reduced equivalent stiffness and the fabrication of optimised plate designs using an electron beam melting (EBM) system. Nonpost-processed EBM plates were assessed against commercially available bone fixation plates in terms of mechanical and biological characteristics. Results show that some redesigned produced plates present mechanical properties similar to the cortical bone and that there is no need to post-process the produced plates in order to establish a good biological bonding with the surrounding tissue.