Additive Manufacturing of Functional Materials (AMFM) Research Group, Centre for Engineering Innovation and Research, University of Wolverhampton, Telford Campus, Telford, TF2 9NT, UK; School of Engineering, Computing and Mathematical Sciences, Faculty of Science and Engineering, University of Wolverhampton, Telford Campus, Telford, TF2 9NT, UK.
Additive Manufacturing of Functional Materials (AMFM) Research Group, Centre for Engineering Innovation and Research, University of Wolverhampton, Telford Campus, Telford, TF2 9NT, UK; School of Engineering, Computing and Mathematical Sciences, Faculty of Science and Engineering, University of Wolverhampton, Telford Campus, Telford, TF2 9NT, UK.
J Mech Behav Biomed Mater. 2022 Oct;134:105409. doi: 10.1016/j.jmbbm.2022.105409. Epub 2022 Aug 12.
Auxetic meta-biomaterials offer unconventional strain behaviour owing to their negative Poisson's ratio (-υ) leading to deformation modes and mechanical properties different to traditional cellular biomaterials. This can lead to favourable outcomes for load-bearing tissue engineering constructs such as bone scaffolds. Emerging early-stage studies have shown the potential of auxetic architecture in increasing cell proliferation and tissue reintegration owing to their -υ. However, research on the development of CoCrMo auxetic meta-biomaterials including bone scaffolds or implants is yet to be reported. In this regard, this paper proposes a potential framework for the development of auxetic meta-biomaterials that can be printed on demand while featuring porosity requirements suitable for load-bearing bone scaffolds. Overall, the performance of five CoCrMo auxetic meta-biomaterial scaffolds characterised under two scenarios for their potential to offer near-zero and high negative Poisson's ratio is demonstrated. Ashby's criterion followed by prototype testing was employed to evaluate the mechanical performance and failure modes of the auxetic meta-biomaterial scaffolds under uniaxial compression. The best performing scaffold architectures are identified through a multi-criteria decision-making procedure combining 'analytic hierarchy process' (AHP) and 'technique for order of preference by similarity to ideal solution' (TOPSIS). The results found the Poisson's ratio for the meta-biomaterial architectures to be in the range of -0.1 to -0.24 at a porosity range of 73-82%. It was found that the meta-biomaterial scaffold (AX1) that offered the highest auxeticity also showed the highest elastic modulus, yield, and ultimate strength of 1.66 GPa, 56 MPa and 158 MPa, respectively. The study demonstrates that the elastic modulus, yield stress, and Poisson's ratio of auxetic meta-biomaterials are primarily influenced by the underlying meta-cellular architecture followed by relative density offering a secondary influence.
超弹性金属基复合材料由于其负泊松比（-υ）而呈现出非常规的应变行为，导致其变形模式和力学性能与传统的多孔生物材料不同。这可能会对承重组织工程结构（如骨支架）产生有利的结果。新兴的早期研究表明，由于其负泊松比，超弹性结构在增加细胞增殖和组织再整合方面具有潜力。然而，关于 CoCrMo 超弹性金属基复合材料（包括骨支架或植入物）的开发研究尚未见报道。在这方面，本文提出了一种潜在的超弹性金属基复合材料开发框架，可以按需打印，同时具有适合承重骨支架的多孔性要求。总的来说，研究了五种 CoCrMo 超弹性金属基生物材料支架的性能，根据其提供近零和高负泊松比的潜力对它们进行了两种情况的特征描述。采用 Ashby 准则和原型测试来评估超弹性金属基生物材料支架在单轴压缩下的力学性能和失效模式。通过结合层次分析法（AHP）和逼近理想解排序法（TOPSIS）的多准则决策程序，确定了性能最佳的支架结构。结果发现，在 73%-82%的孔隙率范围内，超弹性金属基复合材料的泊松比在-0.1 到-0.24 之间。研究发现，提供最大超弹性的金属基复合材料支架（AX1）也显示出最高的弹性模量、屈服强度和极限强度，分别为 1.66GPa、56MPa 和 158MPa。该研究表明，超弹性金属基复合材料的弹性模量、屈服应力和泊松比主要受底层元胞结构的影响，相对密度次之。
