Verma Devendra, Tomar Vikas
School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USA.
School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USA.
Mater Sci Eng C Mater Biol Appl. 2014 Nov;44:371-9. doi: 10.1016/j.msec.2014.08.033. Epub 2014 Aug 15.
The present investigation focuses on understanding the influence of change from wet to dry environment on nanomechanical properties of shallow water shrimp exoskeleton. Scanning Electron Microscopy (SEM) based measurements suggest that the shrimp exoskeleton has Bouligand structure, a key characteristic of the crustaceans. As expected, wet samples are found to be softer than dry samples. Reduced modulus values of dry samples are found to be 24.90 ± 1.14 GPa as compared to the corresponding values of 3.79 ± 0.69 GPa in the case of wet samples. Hardness values are found to be 0.86 ± 0.06 GPa in the case of dry samples as compared to the corresponding values of 0.17 ± 0.02 GPa in the case of wet samples. In order to simulate the influence of underwater pressure on the exoskeleton strength, constant load creep experiments as a function of wet and dry environments are performed. The switch in deformation mechanism as a function of environment is explained based on the role played by water molecules in assisting interface slip and increased ductility of matrix material in wet environment in comparison to the dry environment.
本研究聚焦于理解从潮湿环境转变为干燥环境对浅水虾外骨骼纳米力学性能的影响。基于扫描电子显微镜（SEM）的测量表明，虾外骨骼具有布氏结构，这是甲壳类动物的一个关键特征。正如预期的那样，发现湿样本比干样本更软。干样本的约化模量值为24.90±1.14吉帕，而湿样本的相应值为3.79±0.69吉帕。干样本的硬度值为0.86±0.06吉帕，而湿样本的相应值为0.17±0.02吉帕。为了模拟水下压力对外骨骼强度的影响，进行了作为潮湿和干燥环境函数的恒载蠕变实验。基于水分子在协助界面滑移中所起的作用以及与干燥环境相比湿环境中基体材料延展性增加，解释了变形机制随环境的变化。
