https://scholars.lib.ntu.edu.tw/handle/123456789/576074
標題: | Mechanical and Crack Propagating Behavior of Sierpi?ski Carpet Composites | 作者: | Tsai Y.-Y Chiang Y Buford J.L Tsai M.-L Chen H.-C Chang S.-W. SHU-WEI CHANG |
關鍵字: | Composite structures; Crack propagation; Earthquake engineering; Fractal dimension; Tensile strength; Tensile testing; Advanced engineerings; Engineering applications; Lattice spring model; Mechanical performance; Strength and toughness; Stress-strain response; Structural applications; Two dimensional spaces; Cracks | 公開日期: | 2021 | 來源出版物: | ACS Biomaterials Science and Engineering | 摘要: | Fractals, mathematically defined as "self-similar subsets at different scales", are ubiquitous in nature despite their complexity in assembly and formulation. Fractal geometry formed by simple components has long been applied to many fields, from physics and chemistry to electronics and architecture. The Sierpi?ski carpet (SC), a fractal with a Hausdorff dimension of approximately 1.8933, has two-dimensional space-filling abilities and therefore provides many structural applications. However, few studies have investigated its mechanical properties and fracture behaviors. Here, utilizing the lattice spring model (LSM), we constructed SC composites with two base materials and simulated tensile tests to show how fractal iterations affect their mechanical properties and crack propagation. From observing the stress-strain responses, we find that, for either the soft-base or stiff-base SC composites, the second iteration has the optimal mechanical performance in the terms of stiffness, strength, and toughness compared to the composites with higher hierarchies. The reason behind this surprising result is that the largest stress intensities occur at the corners of the smallest squares in the middle zone, which consequently induces crack nucleation. We also find that the main crack tends to deflect locally in SC composites with a soft matrix, but in global main crack behavior, SC composites with a stiff matrix have a large equivalent crack deflection. Furthermore, considering the inherent anisotropy of SC composites, we rotated the samples by 45°. The results show that the tensile strength and toughness of rotated SC composites are inferior and the crack propagating behaviors are distinct from the standard SC composites. This finding infers advanced engineering for crack control and deflection by adjusting the orientation of SC composites. Overall, our study opens the door for future engineering applications in stretchable devices, seismic metamaterials, and structural materials with tunable properties and hierarchies. ? |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85105098565&doi=10.1021%2facsbiomaterials.0c01595&partnerID=40&md5=94dcc069d05b5e83d1c8e526ef606d4d https://scholars.lib.ntu.edu.tw/handle/123456789/576074 |
ISSN: | 23739878 | DOI: | 10.1021/acsbiomaterials.0c01595 |
顯示於: | 土木工程學系 |
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