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Biwei Deng Rong Xu Kejie Zhao Yongfeng Lu Sabyasachi Ganguli Gary J. Cheng 《Materials Today》2018,21(5):467-474
Manufacturing ultralight and mechanical reliable materials has been a long-time challenge. Ceramic-based mechanical metamaterials provide significant opportunities to reverse their brittle nature and unstable mechanical properties and have great potential as strong, ultralight, and ultrastiff materials. However, the failure of ceramics nanolattice and degradation of strength/modulus with decreasing density are caused by buckling of the struts and failure of the nodes within the nanolattices, especially during cyclic loading. Here, we explore a new class of 3D ceramic-based metamaterials with a high strength–density ratio, stiffness, recoverability, cyclability, and optimal scaling factor. Deformation mode of the fabricated nanolattices has been engineered through the unique material design and architecture tailoring. Bending-dominated hollow nanolattice (B-H-Lattice) structure is employed to take advantages of its flexibility, while a few nanometers of carbonized mussel-inspired bio-polymer (C-PDA) is coherently deposited on ceramics’ nanolayer to enable non-buckling struts and bendable nodes during deformation, resulting in reliable mechanical properties and outperforming the current bending-dominated lattices (B-Lattices) and carbon-based cellulose materials. Meanwhile, the structure has comparable stiffness to stretching-dominated lattices (S-Lattices) while with better cyclability and reliability. The B-H-Lattices exhibit high specific stiffness (>106?Pa·kg?1·m?3), low-density (~30?kg/m3), buckling-free recovery at 55% strain, and stable cyclic loading behavior under up to 15% strain. As one of the B-Lattices, the modulus scaling factor reaches 1.27, which is lowest among current B-Lattices. This study suggests that non-buckling behavior and reliable nodes are the key factors that contribute to the outstanding mechanical performance of nanolattice materials. A new concept of engineering the internal deformation behavior of mechanical metamaterial is provided to optimize their mechanical properties in real service conditions. 相似文献
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Zan Wu Zhang Qiaochu Xu Hu Liao Fuyou Guo Zhongxun Deng Jianan Wan Jing Zhu Hao Chen Lin Sun Qingqing Ding Shijin Zhou Peng Bao Wenzhong Zhang David Wei 《Nano Research》2018,11(7):3739-3745
Nano Research - A spin-coating method was applied to obtain thinner and smoother PEO/LiClO4 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a... 相似文献
105.
Baobin Xie Shenyou Peng Jia Li Qihong Fang Peter K. Liaw 《Advanced Engineering Materials》2023,25(19):2300146
The evolution of the dislocation density induced by the nanomachining process dominates the plastic deformation behaviors of materials, thus affecting the mechanical properties significantly. However, a challenging topic related to how to establish an accurate model for predicting the dislocation density based on the limited simulations and experiments arises due to the complicated thermal–mechanical coupling mechanism during the machining process. Herein, a multistage method integrating machine learning, physics, and high-throughput atomic simulation is proposed to investigate the effect of cutting speed on the dislocation behavior in polycrystal copper. Compared with the traditional one-step machine learning method, the constraint of physical features effectively improves the accuracy and generalization ability of the model. The results indicate that the dislocation behaviors depend on the competition between the cutting force and temperature. In the low-cutting speed, the predominated role of the cutting temperature leads to a rapid decline of the dislocation density. In contrast, the dislocation density tends to be stable under a high-speed cutting process due to the dynamic balance between the effects of the cutting force and temperature. Notably, the proposed strategy provides a new and universal framework to design the machining parameters to obtain high-quality products. 相似文献
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利用小波的带通性质 ,给出了一种新的小波预处理方法 .实验表明 ,经过小波预处理后提取的特征 ,提高了语音的识别率 相似文献
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彭晓玲 《重庆科技学院学报(社会科学版)》1998,(3)
在市场经济的冲击下,我国青年现阶段的价值观发生了很大的变化,主要表现为:一元化价值观向多元化价值观演变;理想主义价值取向转为务实求实的价值取向;群体本位向个体本位取向偏移。在这个价值观转变当中,往往出现一些畸形的价值取向,所以应坚持正确的导向,强化新的价值观。 相似文献
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