Multidimensional Mechanics of Three-Dimensional Printed and Micro-Architectured Scaffolds.
Multidimensional Mechanics of Three-Dimensional Printed and Micro-Architectured Scaffolds.
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DOI：
10.1115/1.4051182
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
Pooya Niksiar;Zhaoxu Meng;M. Porter
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文献类型：
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作者：
Pooya Niksiar;Zhaoxu Meng;M. Porter
多孔材料的力学性能取决于其微结构特性。冷冻注模成型是制备微结构多孔支架的有效方法。在冷冻铸造过程中产生的三个关键特征是壁厚、横截面上的磁区数量以及连接相邻墙壁的横向桥梁。为了具体研究这些结构特征对支架力学性能和各向异性压缩性能的影响，我们利用加法制造，即3D打印，一次制造出具有不同特征的严格设计的立方体支架。然后，我们比较了支架的三个垂直方向(包括纵向和横向)的强度、韧性、回弹、刚度和应变与破坏的关系。为了在一张图中比较这些多维力学，我们使用以前开发的雷达图方法来评估不同的支架并揭示结构特征的影响。我们发现，微结构特性可以有效地调谐多维力学。值得注意的是，脚手架的抗屈曲能力取决于所有这三种结构特征。我们的结果表明，微区数目的增加导致了三个方向上韧性的增强。增加壁厚会提高机械性能，但代价是失去小孔，这在某些应用中是不受欢迎的。此外，增加横桥不仅提高了支架的横向强度，还提高了支架的纵向强度，同时也提高了支架的抗屈曲能力。我们的研究为3D打印微结构多孔支架的结构-性能关系提供了重要的见解。
Mechanical properties of porous materials depend on their micro-architectural characteristics. Freeze casting is an effective method to fabricate micro-architectured porous scaffolds. Three key characteristics generated during freeze casting are wall thickness, number of domains at the cross-section, and transverse bridges connecting adjacent walls. To specifically study the effect of these structural characteristics on the mechanics and anisotropic compressive properties of scaffolds, we utilize additive manufacturing, i.e., 3D printing, to fabricate strictly designed cubic scaffolds with varying one characteristic at a time. We then compare strength, toughness, resilience, stiffness, and strain to failure in three orthogonal directions of the scaffolds, including longitudinal and transverse directions. To compare these multidimensional mechanics in a single diagram, we use a previously developed radar chart method to evaluate different scaffolds and unravel the effect of the structural characteristics. We find that the multidimensional mechanics can be effectively tuned by the micro-architectural characteristics. Notably, the buckling resistance of the scaffolds depends on all three structural characteristics. Our results show that an increased number of domains leads to enhanced toughness in all three directions. Increasing wall thickness leads to enhanced mechanical properties but comes at the price of losing small-sized pores, which is not favored for certain applications. In addition, adding transverse bridges increase not only the transverse strength of the scaffolds but also the longitudinal strength as they also enhance the buckling resistance. Our study provides important insights into the structure-property relationships of 3D-printed micro-architectured porous scaffolds.