Frequency Analysis and Anti-Shock Mechanism of Woodpecker's Head Structure
Frequency Analysis and Anti-Shock Mechanism of Woodpecker's Head Structure
复制标题
啄木鸟头部结构频率分析及抗震机理
DOI：
10.1016/s1672-6529(14)60045-7
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发表时间：
2014-04-01
影响因子：
4
通讯作者：
Zhang, Wei
中科院分区：
文献类型：
--
作者：
Zhu, Zhaodan;Wu, Chengwei;Zhang, Wei
通过实验和数值模拟研究了啄木鸟头骨的力学特性和头部的抗冲击特性。利用纳米压痕法测量了颅骨的微观杨氏模量，并利用均匀化理论计算了颅骨不同位置的宏观等效杨氏模量。基于啄木鸟头部的CT图像，建立了完整对称的啄木鸟颅骨及其内部结构的有限元模型，并进行了模态分析和应力谱分析。数值结果表明，在舌骨上施加预拉力可以提高啄木鸟头部的固有频率。25 N预拉力下的第一阶固有频率达到57 Hz，比无预拉力状态提高了21.3%，是啄木鸟工作频率（20 Hz 25 Hz）的两倍多。在对喙尖施加0.6 ms的冲击力时，在100 Hz和8，000 Hz附近出现高幅度的应力分量，远离啄木鸟头部的工作频率和固有频率。自然频率、工作频率和应激反应频率之间的巨大差距使啄木鸟能够有效地保护其大脑免受共振损伤。
The mechanical properties of the skull and the anti-shock characteristics of woodpecker's head were investigated by experiment and numerical simulation. We measured the micro-Young's modulus of the skull by nano-indentation method and calculated the macro-equivalent Young's modulus of the skull at different positions using homogenization theory. Based on the Computerized Tomography (CT) images of woodpecker head, we then built complete and symmetric finite element models of woodpecker's skull and its internal structure and performed modal analysis and stress spectrum analysis. The numerical results show that the application of pre-tension force to the hyoid bone can increase the natural frequency of woodpecker's head. The first natural frequency under the pre-tension force of 25 N reaches 57 Hz, which is increased by 21.3% from the non-pre-tension state and is more than twice the working frequency of woodpecker (20 Hz 25 Hz). On the application of impact force to the tip of beak for 0.6 ms, high magnitudes of stress component occur at around 100 Hz and 8,000 Hz, far away from both the working frequencies and the natural frequencies of woodpecker head. The large gaps among the natural, working and stress response frequencies enable the woodpecker to effectively protect its brain from the resonance injury.