利用電腦模擬計算啟發自竹子及骨頭之複合結構的力學行為

Mechanical Properties of Composite Structure Inspired from Bamboo and Bone Using Computer Simulations

陳憲君(Hsien-Chun Chen)

指導教授 ： 張書瑋

國立臺灣大學/工學院/土木工程學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202201267

摘要

現今的材料科學中，為了設計出高性能的創新結構材料，常以生物中的結構作為設計靈感來源。生物結構中，通常以脆性的礦物質以及延性的蛋白質兩種極端的材料所組成，在藉由不同尺度的特殊組合方式提高性能，並且通常比人造材料更優秀，因此許多人在仿生的領域做了許多研究。在本研究中將會設計以骨頭和竹子所啟發之仿生複合材料結構，並且討論此結構的拓撲行為和斷裂性質之關聯性。
骨頭是一個階層式結構，結構會因尺度而不同，在本研究中模仿了骨頭中的孔洞，利用橢圓形的填充材料均勻分布在矩形的基底材料，設計出仿骨頭複合材料。而在竹子結構的方面，主要為中空管狀的結構，且剖面上的體積分率分布成梯度狀，本研究中擷取竹子梯度狀的體積分率特性，基於上述的仿骨頭複合材料，將均勻的體積分率不同的分佈方式取代，設計出同時擁有骨頭以及竹子特性的仿生複合材料。在此設計中，體積分率分佈方式分為三種，分別為改變梯度範圍的梯度系列、在梯度區排序系列以及全模型排序系列。在材料方面，基底使用硬材料、填充使用軟材料以及基底使用軟材料、填充使用硬材料兩種方式做組合。
在模擬中，本研究使用了二維三角晶格彈簧模型，進行電腦計算預測本研究所設計的仿生複合材料之性質，其中主要包含裂紋發展以及斷裂性質。藉由模擬所得的資訊以及視覺化的軟體，了解體積分率分布和裂紋機制的關聯性，進而釐清模型拓撲行為對斷裂性質的影響因子。在本研究所設計的模型中，得知體積分率排序對強度、韌性兩方面可影響至1.7倍，且可設計出在保有和硬材料相同的強度前提，提升韌性達30%。

關鍵字

骨頭 ； 竹子 ； 複合材料 ； 二維三角晶格彈簧模型 ； 斷裂性質 ； 裂紋機制

並列摘要

In materials science, to design innovative structural materials with high performance, structures in biology are often used as design inspirations. Biological structures, it is usually composed of two extreme materials, brittle minerals and ductile proteins. Biological structures improve performance through special combinations of different scales, and are usually better than man-made materials, so many people have done a lot of research in the field of bionics. In this study, a biomimetic composite structure inspired by bone and bamboo will be designed and the relationship between the topological behavior and fracture properties of the structure will be discussed.
Bone is a hierarchical structure, and its structure varies with scales. In this study, structure of the holes in the bone were imitated, and the oval filling material was evenly distributed in the rectangular base material to design a bone-like composite material. In terms of bamboo structure, it is mainly a hollow tubular structure, and the volume fraction distribution on the cross-section is gradient. In this study, the above-mentioned bone-like composite materials and the gradient volume fraction characteristics of bamboo are considered. A bionic composite material with both properties of bone and bamboo was designed by replacing the uniform volume fraction with different distribution methods. In this design, the volume fraction distribution methods are divided into three series, namely, Gradient series, Shuffle Gradient series, and Shuffle Whole series. Two combinations of materials are used: hard materials for the matrix, soft materials for the inclusion, and soft materials for the matrix, hard materials for the inclusion.
This study uses a two-dimensional triangular lattice spring model to perform computer calculations in predicting the properties of the biomimetic composites designed, including crack development and fracture properties. With the information obtained from the simulation and the visualization, the correlation between the volume fraction distribution and the crack mechanism stood, and the influencing factors of the model topological behavior on the fracture properties are clarified. In the model designed in this study, the order of volume fraction affects the strength and toughness up to 1.7 times, and it maintains the same strength as the hard material, and increases the toughness by 30%.

並列關鍵字

bone ； bamboo ； composite material ； 2D triangular lattice spring model ； fracture properties ； crack mechanism

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