科學家揭示鐵甲蟲鞘翅的增韌機理
作者：
小柯機器人發布時間：2020/10/25 21:56:15
美國加利福尼亞大學David Kisailus研究團隊發現鐵甲蟲鞘翅的增韌機理。相關論文於2020年10月21日發表在《自然》雜誌上。
他們使用先進的顯微鏡、光譜學和原位機械測試方法，在該甲蟲的外骨骼中識別了大規模結構樣式，並研究了由此產生的機械響應和增韌機理。他們重點介紹了一系列相互交叉的縫線，其橢圓形的幾何形狀和層壓的微結構在關鍵應變下提供了機械互鎖和增韌作用，同時避免了災難性的故障。這些觀察結果可用於開發用於連接異種材料的堅韌、抗衝擊和抗壓的材料。他們通過從仿生複合材料創建互鎖縫線來證明這一點，與常用工程接頭相比，該縫線顯示出更高的韌性。
據介紹，將異種材料（例如塑料和金屬）結合到工程結構中仍然是一個挑戰。機械緊固，常規焊接和粘合劑粘結是目前用於此目的的技術示例，但是這些方法中的每一種都存在其自身的一系列問題，例如應力集中器的形成或在環境暴露下的降解，強度降低並導致過早失效。在眾多動植物物種的生物組織中，已經開發出有效的策略來合成、構建和整合具有卓越機械性能的複合材料。鐵甲蟲Phloeodes diabolicus的骨骼前爪（elytra）就是很好的例子。由於缺乏逃避捕食者的能力，這種沙漠昆蟲具有極強的抗衝擊和抗壓碎鞘翅，由複雜且漸變的界面產生。
附：英文原文
Title: Toughening mechanisms of the elytra of the diabolical ironclad beetle
Author: Jesus Rivera, Maryam Sadat Hosseini, David Restrepo, Satoshi Murata, Drago Vasile, Dilworth Y. Parkinson, Harold S. Barnard, Atsushi Arakaki, Pablo Zavattieri, David Kisailus
Issue&Volume: 2020-10-21
Abstract: Joining dissimilar materials such as plastics and metals in engineered structures remains a challenge1. Mechanical fastening, conventional welding and adhesive bonding are examples of techniques currently used for this purpose, but each of these methods presents its own set of problems2 such as formation of stress concentrators or degradation under environmental exposure, reducing strength and causing premature failure. In the biological tissues of numerous animal and plant species, efficient strategies have evolved to synthesize, construct and integrate composites that have exceptional mechanical properties3. One impressive example is found in the exoskeletal forewings (elytra) of the diabolical ironclad beetle, Phloeodes diabolicus. Lacking the ability to fly away from predators, this desert insect has extremely impact-resistant and crush-resistant elytra, produced by complex and graded interfaces. Here, using advanced microscopy, spectroscopy and in situ mechanical testing, we identify multiscale architectural designs within the exoskeleton of this beetle, and examine the resulting mechanical response and toughening mechanisms. We highlight a series of interdigitated sutures, the ellipsoidal geometry and laminated microstructure of which provide mechanical interlocking and toughening at critical strains, while avoiding catastrophic failure. These observations could be applied in developing tough, impact- and crush-resistant materials for joining dissimilar materials. We demonstrate this by creating interlocking sutures from biomimetic composites that show a considerable increase in toughness compared with a frequently used engineering joint. A jigsaw-style configuration of interlocking structures identified in the elytra of the remarkably tough diabolical ironclad beetle, Phloeodes diabolicus, is used to inspire crush-resistant multilayer composites for engineering joints.
DOI: 10.1038/s41586-020-2813-8
Source: https://www.nature.com/articles/s41586-020-2813-8