Mechanical Engineering Program, School of Science, Engineering and Technology, Penn State Harrisburg, Middletown, PA, 17057, United States; Department of Biomedical Engineering, Pennsylvania State University, University Park, State College, PA, 16802, United States.
Mechanical Engineering Program, School of Science, Engineering and Technology, Penn State Harrisburg, Middletown, PA, 17057, United States; Shenzhen Key Laboratory of Soft Mechanics & Smart Manufacturing, Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
J Mech Behav Biomed Mater. 2024 Jul;155:106555. doi: 10.1016/j.jmbbm.2024.106555. Epub 2024 Apr 17.
Recently, the replication of biological microstructures has garnered significant attention due to their superior flexural strength and toughness, coupled with lightweight structures. Among the most intriguing biological microstructures renowned for their flexural strength are those found in the Euplectella Aspergillum (EA) marine sponges. The remarkable strength of this sponge is attributed to its complex microstructure, which consists of concentric cylindrical layers known as spicules with organic interlayers. These features effectively impede large crack propagation, imparting extraordinary mechanical properties. However, there have been limited studies aimed at mimicking the spicule microstructure. In this study, structures inspired by spicules were designed and fabricated using the stereolithography (SLA) 3D printing technique. The mechanical properties of concentric cylindrical structures (CCSs) inspired by the spicule microstructure were evaluated, considering factors such as the wall thickness of the cylinders, the number of layers, and core diameter, all of which significantly affect the mechanical response. These results were compared with those obtained from solid rods used as solid samples. The findings indicated that CCSs with five layers or fewer exhibited a flexural strength close to or higher than that of solid rods. Particularly, samples with 4 and 5 cylindrical layers displayed architecture similar to natural spicules. Moreover, in all CCSs, the absorbed energy was at least 3-4 times higher than solid rods. Conversely, CCSs with a cylinder wall thickness of 0.65 mm exhibited a more brittle behavior under the 3-point bending test than those with 0.35 mm and 0.5 mm wall thicknesses. CCSs demonstrated greater resistance to failure, displaying different crack propagation patterns and shear stress distributions under the bending test compared to solid rods. These results underscore that replicating the structure of spicules and producing structures with concentric cylindrical layers can transform a brittle structure into a more flexible one, particularly in load-bearing applications.
最近，由于生物微观结构具有优越的弯曲强度和韧性，以及轻质结构，其复制引起了人们的极大关注。在以弯曲强度而闻名的最有趣的生物微观结构中，有一些存在于 Euplectella Aspergillum（EA）海洋海绵中。这种海绵的强度非常高，是因为其复杂的微观结构，它由同心圆柱层组成，称为有有机夹层的刺。这些特征有效地阻止了大裂缝的扩展，赋予了其非凡的机械性能。然而，目前针对模仿刺微观结构的研究还很有限。在这项研究中，使用立体光刻（SLA）3D 打印技术设计和制造了受刺启发的结构。考虑到圆柱体的壁厚、层数和芯直径等因素，评估了受刺微观结构启发的同心圆柱结构（CCS）的机械性能，这些因素对机械响应有很大的影响。将这些结果与用作实心样品的实心棒的结果进行了比较。结果表明，具有五层或更少层的 CCS 的弯曲强度接近或高于实心棒。特别是具有 4 和 5 个圆柱层的样品具有类似于天然刺的结构。此外，在所有 CCS 中，吸收的能量至少比实心棒高 3-4 倍。相反，在 3 点弯曲测试中，壁厚为 0.65mm 的 CCS 表现出比壁厚为 0.35mm 和 0.5mm 的 CCS 更脆的行为。CCS 在弯曲测试中表现出更高的抗失效能力，与实心棒相比，显示出不同的裂纹扩展模式和剪切应力分布。这些结果表明，复制刺的结构并生产具有同心圆柱层的结构可以将脆性结构转变为更灵活的结构，特别是在承载应用中。
