{"title":"Micro-structural and micro-mechanical characterization of rock-boring angelwing clams","authors":"Yumeng Zhao, Sheng Dai","doi":"10.1016/j.actbio.2024.10.007","DOIUrl":null,"url":null,"abstract":"<div><div>Rock-boring behavior is a common phenomenon among certain bivalve clams, yet the mechanisms enabling this capability remain elusive. This study delves into the microstructural and micromechanical properties of the shells and denticles of angelwing (<em>Cyrtopleura costata</em>), a rock-boring clam. X-ray Diffraction Analysis and Energy-dispersive Spectroscopy identify that angelwing shells are made of pure aragonite. Scanning Electron Microscope images reveal that angelwing shells are mostly made of submicrometer-thick lamellar sheets, which are packed closely forming crossed-lamellar groups. Nanoindentation tests yield Young’s Moduli of <span><math><mrow><mn>30</mn><mo>−</mo><mn>70</mn><mspace></mspace><mi>G</mi><mi>P</mi><mi>a</mi></mrow></math></span> and hardness of <span><math><mrow><mn>3</mn><mo>−</mo><mn>10</mn><mspace></mspace><mi>G</mi><mi>P</mi><mi>a</mi></mrow></math></span> at different parts of the shells, making angelwing clam shells among the hardest biological materials. Further numerical simulations validate that the crossed-lamellar microstructure excels in withstanding external loads and safeguarding the integrity of the shell through minimized stress concentration.</div></div><div><h3>Statement of significance</h3><div>Boring and drilling in rocks are important for construction, energy, and scientific exploration. Nature offers ideas for improving these techniques, as seen in the rock-boring angelwing clam. Our study focuses on the mechanical and micro-structural properties of the clam’s shell, which help it bore into rocks. Through nanoindentation, we found that the clam’s shell is one of the hardest and stiffest biological shells, a key factor in its boring ability. We also identified intricate shell structures that likely enhance its strength and resistance to mechanical stress. These findings highlight important bio-material traits that could inspire new, more efficient drilling technologies for human use.</div></div>","PeriodicalId":237,"journal":{"name":"Acta Biomaterialia","volume":"190 ","pages":"Pages 423-434"},"PeriodicalIF":9.4000,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Biomaterialia","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1742706124005907","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, BIOMEDICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Rock-boring behavior is a common phenomenon among certain bivalve clams, yet the mechanisms enabling this capability remain elusive. This study delves into the microstructural and micromechanical properties of the shells and denticles of angelwing (Cyrtopleura costata), a rock-boring clam. X-ray Diffraction Analysis and Energy-dispersive Spectroscopy identify that angelwing shells are made of pure aragonite. Scanning Electron Microscope images reveal that angelwing shells are mostly made of submicrometer-thick lamellar sheets, which are packed closely forming crossed-lamellar groups. Nanoindentation tests yield Young’s Moduli of and hardness of at different parts of the shells, making angelwing clam shells among the hardest biological materials. Further numerical simulations validate that the crossed-lamellar microstructure excels in withstanding external loads and safeguarding the integrity of the shell through minimized stress concentration.
Statement of significance
Boring and drilling in rocks are important for construction, energy, and scientific exploration. Nature offers ideas for improving these techniques, as seen in the rock-boring angelwing clam. Our study focuses on the mechanical and micro-structural properties of the clam’s shell, which help it bore into rocks. Through nanoindentation, we found that the clam’s shell is one of the hardest and stiffest biological shells, a key factor in its boring ability. We also identified intricate shell structures that likely enhance its strength and resistance to mechanical stress. These findings highlight important bio-material traits that could inspire new, more efficient drilling technologies for human use.
凿岩行为是某些双壳类蛤蜊的常见现象,但这种能力的实现机制仍然难以捉摸。本研究深入探讨了钻石蛤--天使翼(Cyrtopleura costata)贝壳和齿柱的微结构和微机械特性。通过 X 射线衍射分析和能量色散光谱分析发现,天使翼的贝壳是由纯文石构成的。扫描电子显微镜图像显示,天使翼的贝壳主要由亚微米厚的薄片组成,这些薄片紧密排列,形成交叉薄片群。纳米压痕测试得出贝壳不同部位的杨氏模量为30-70GPa,硬度为3-10GPa,使天使翼蛤的贝壳成为最坚硬的生物材料之一。进一步的数值模拟验证了交叉层状微结构在承受外部载荷方面的优异性能,并通过最大限度地减少应力集中来保护贝壳的完整性。意义说明:在岩石中钻孔和凿洞对建筑、能源和科学探索非常重要。大自然为这些技术的改进提供了思路,这一点在钻岩天使翼蛤身上可以看到。我们的研究侧重于蛤壳的机械和微观结构特性,这些特性有助于它钻入岩石。通过纳米压痕法,我们发现蛤蜊的外壳是生物外壳中最坚硬和最坚硬的,这是其钻孔能力的一个关键因素。我们还发现了复杂的贝壳结构,这些结构可能增强了贝壳的强度和抗机械应力的能力。这些发现凸显了重要的生物材料特性,可为人类使用更高效的新型钻探技术提供灵感。
期刊介绍:
Acta Biomaterialia is a monthly peer-reviewed scientific journal published by Elsevier. The journal was established in January 2005. The editor-in-chief is W.R. Wagner (University of Pittsburgh). The journal covers research in biomaterials science, including the interrelationship of biomaterial structure and function from macroscale to nanoscale. Topical coverage includes biomedical and biocompatible materials.