蜻蜓翅膀是一種輕、堅固、強韌的天然材料，具有很高的抗彎強度。由於蜻蜓翅膀的突出特性，使蜻蜓成為飛行能力最强的生物。此優異的生物材料激發了我們的好奇心，並激勵我們以這種生物靈感設計結構。通過觀察蜻蜓翅脈，我們試圖闡明影響仿生結構力學效能的關鍵參數。
這項研究從生物學觀察開始。蜻蜓翅膀具有水滴形狀、隨機分佈的翅脈結構，並將翅膀分成幾個區域，稱為主脈與橫脈(次脈)。我們發現橫脈可以用沃羅諾伊結構的數學形式來描述。我們進一步量測了橫脈的每個質心，發現了規則度的參數，可用來描述結構的無序程度。接下來，我們使用Python自動生成沃羅諾伊結構，這些結構被用作基因演算法的初始母代。利用基於影像的oof2模擬軟體，可計算每個個體的適應值。然後選擇具有較高適應值的結構並進入繁衍（交叉和變異）過程。在繁衍過程中，將基於輸入的母代結構生成新子代結構。上述步驟會重複30次，直到最終得到基因演算法優化的結構。
利用ImageJ對蜻蜓翅脈和生成的Voronoi結構的幾何因素進行了分析和比較。實際翅翼與生成翅翼的比較結果表明，生成翅翼的結構與實際翅翼有一定的相似性。透過3D列印實現基因演算法優化的二維沃羅諾伊結構的力學性能。在本研究中，這些多孔結構由光固化 3D列印機設計和列印，並以每分鐘6%之應變率進行拉伸試驗。數位影像相關法（DIC）是一種像素級的影像追蹤方法，在本實驗中使用影像跟踪技術來研究裂紋的擴展和變形行為。結果表明，基因演算法優化後的結構在剛度、强度、韌性分別提高了30%、40%、18%。數位影像相關法結果顯示了裂紋在高應變區萌生和擴展的過程並闡明Voronoi結構的三階段變形機制。此研究在需要輕、高强度、高韌性資料的仿生微型飛行器領域具有潛在的應用前景。
此研究在需要輕、高强度、高韌性資料的仿生微型飛行器領域具有潛在的應用前景。

Dragonfly wings are lightweight, strong, and tough natural materials with high flexural strength. Due to the outstanding characteristics of the dragonfly wing, it makes the dragonfly become the creature with superior flight ability. This excellent biological material arouses our curiosity and inspires us to design structures with this bio-inspiration. By observing the dragonfly wing vein, we tried to elucidate the key parameters that affect the mechanical properties of bio-inspired structures.
This study began with observation of the dragonfly wing. Dragonfly wing possesses water droplet-shape with randomly distributed structures divided the wing into several regions, named cross-veins. We discovered that the cross-veins could be described by a mathematical form of the Voronoi structure. Then, we measured each centroid in cross-veins and found a parameter, regularity, which describes how disorder the structure is. Next, we used a customized Python script to generate the Voronoi structures automatically. These structures were used as the initial generation of genetic algorithm. By applying the image-based oof2 simulation software, the fitness value can be calculated for each individual. Then, structures with higher fitness values were selected and entered the reproduction (crossover and mutation) process. During the reproduction process, a new structure was generated based on the structure of the input. The above steps were repeated for 30 times until we finally obtained the GA-improved structures.
The geometric factor of both dragonfly wing veins and generated Voronoi structure were analyzed and compared by ImageJ. The results of comparison between the actual wing and the generated one indicated that the latter's structure had a certain degree of similarity to that of the former. The mechanical properties of the GA-improved two-dimensional Voronoi structures were realized by 3D printing technology and mechanical testing. In this study, these porous structures were designed and printed by an SLA 3D printer, and a universal testing machine with a strain rate of 6% per minute was used for tensile testing. The Digital Image Correlation method (DIC) is an optical method that uses image tracking technology to study crack growth and deformation behavior in this experiment. The results showed that the stiffness, strength, toughness of the GA-improved structures increase 30%, 40%, 18%, respectively. The DIC results showed crack initiation and propagation at the high strains. The three-stage failure mechanism of the Voronoi structure was also clarified in this study. This study has the potential to be applied in the field of biomimetic micro-aerial vehicles, in which lightweight, high strength, and high toughness material is required.

Content
摘要 2
Abstract 4
Content 8
Figure Caption 10
Table Caption 21
Chapter 1 Introduction 22
Chapter 2 Literature Review 24
2.1 Biological Material and Bio-Inspired Material: 24
2.2 Voronoi structures 32
2.3 Dragonfly Wing Case Study 40
2.4 Digital Image Correlation Analysis 44
2.5 Genetic Algorithm 47
Chapter 3 Experimental Methods 56
3.1 Dragonfly Wing Inspired Model Designs 58
3.2 Genetic Algorithm 62
3.3 Geometry Analysis 65
3.4 Stereolithography 3D Printing Technique 67
3.5 Universal Tensile Testing 70
3.6 Digital Image Correlation(DIC) Technique 72
Chapter 4 Results and Discussion 75
4.1 Dragonfly wing observation 75
4.2 Voronoi Structure Generation and Genetic Algorithm 85
4.3 Geometric Analysis 94
4.4 Mechanical Properties of Different Regularity Model 106
4.5 Digital Image Correlation and Fracture Mechanism 120
Chapter 5 Conclusion 129
Chapter 6 Future Work 132
6.1 Composite material of Voronoi structures 132
6.2 Mechanical properties of various wing models 133
6.3 3D Voronoi structures 135
References 136

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