Department of Engineering and Materials Science and Transportation, University of Seville, Av. Camino de los Descubrimientos s/n, 41092 Seville, Spain.
Department of Engineering and Materials Science and Transportation, University of Seville, Av. Camino de los Descubrimientos s/n, 41092 Seville, Spain.
J Mech Behav Biomed Mater. 2018 Apr;80:88-96. doi: 10.1016/j.jmbbm.2018.01.026. Epub 2018 Jan 31.
Commercially pure Titanium (cpTi) and its alloys are the most successful metallic biomaterials for bone replacement, due to its excellent biomechanical and biofunctional balance. However, these materials have higher elastic modulus when compared with bone, leading to the stress-shielding phenomenon and promoting bone resorption. Development of porous implants with low elastic modulus, providing a good mechanical and functional balance (suitable mechanical strength and optimum osseointegration), is the focus of emergent research in advanced Ti-based alloy biomaterials. With the aim of understanding the mechanical behaviour of porous materials with relation to the porosity level and the porous morphology, a new improved model with three different versions have been developed in this work. The proposed FE model combines the simplicity of a 2D periodic geometry with the complex information of the pore morphology extracted from experimentation. The methodology to generate the 2D simulated microstructure is based on a series of nxn pores distributed in a square matrix. The different versions of the model differ in the way of building the porous geometry. In the first version of the model ("Basic-Pattern Model"), the pores are supposed to be circular and periodically distributed in the matrix, following a perfect pattern. The second version of the model ("Pattern Model") is similar to the previous one, but with elliptic pores with a morphology randomly generated, following statistical information from experiments. In the third version ("Semi-random Model"), a controlled random distribution of the pores is obtained by including a randomness factors in both directions. By making use of the proposed FE model with its different versions, five different porous titanium obtained by the space-holders technique (with porosities θ = 28%, 37%, 47%, 57% and 66%) have been modeled based on experimental information of the pore morphology, and its macroscopic mechanical behaviour has been simulated, showing relatively good agreement with experimental results.
商用纯钛（cpTi）及其合金是最成功的骨替代金属生物材料，因为它具有出色的生物力学和生物功能平衡。然而，与骨相比，这些材料的弹性模量更高，导致应力屏蔽现象，并促进骨吸收。开发具有低弹性模量的多孔植入物，提供良好的机械和功能平衡（适当的机械强度和最佳的骨整合），是先进钛基合金生物材料研究的重点。为了了解多孔材料的力学性能与孔隙率水平和多孔形态的关系，本工作中开发了一种具有三种不同版本的新型改进模型。所提出的有限元模型将二维周期性几何形状的简单性与从实验中提取的孔形态的复杂信息结合在一起。生成二维模拟微观结构的方法基于分布在正方形矩阵中的 nx n 个孔的系列。模型的不同版本在构建多孔几何形状的方式上有所不同。在模型的第一个版本（“基础图案模型”）中，假设孔是圆形的，并按照完美的图案周期性地分布在基质中。模型的第二个版本（“图案模型”）类似于前一个模型，但具有随机生成的形态的椭圆形孔，遵循来自实验的统计信息。在第三个版本（“半随机模型”）中，通过在两个方向上都包含随机性因素，获得了孔的受控随机分布。通过使用具有不同版本的建议有限元模型，基于孔形态的实验信息对通过空间保持剂技术获得的五种不同多孔钛（孔隙率θ分别为 28%、37%、47%、57%和 66%）进行建模，并模拟了其宏观力学行为，与实验结果显示出相对较好的一致性。
