Yang Yang, Wang Yongquan
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
Adv Sci (Weinh). 2024 Jan;11(3):e2307088. doi: 10.1002/advs.202307088. Epub 2023 Nov 23.
The replication of jumping motions observed in small organisms poses a significant challenge due to size-related effects. Shape memory alloys (SMAs) exhibit a superior work-to-weight ratio, making them suitable for jumping actuators. However, the SMAs advantages are hindered by the limitations imposed by their single actuator configuration and slow response speed. This study proposes a novel design approach for an insect-scale shape memory alloy jumper (net-shell) using 4D printing technology and the bistable power amplification mechanism. The energy variations of the SMA net-shell under different states and loads are qualitatively elucidated through a spring-mass model. To optimize the performance of the SMA net-shell, a non-contact photo-driven technique is employed to induce its shape transition. Experimental investigations explore the deformation response, energy release of the net-shell, and the relationship between the light power density. The results demonstrate that the SMA net-shell exhibits remarkable jumping capabilities, achieving a jump height of 60 body lengths and takeoff speeds of up to 300 body lengths per second. Furthermore, two illustrative cases highlight the potential of net-shells for applications in unstructured terrains. This research contributes to miniaturized jumping mechanisms by providing a new design approach integrating smart materials and advanced structures.
由于尺寸相关效应，在小型生物体中观察到的跳跃运动的复制带来了重大挑战。形状记忆合金（SMA）具有优异的功重比，使其适用于跳跃致动器。然而，SMA的优势受到其单致动器配置和缓慢响应速度的限制。本研究提出了一种使用4D打印技术和双稳态功率放大机制的昆虫尺度形状记忆合金跳跃器（网壳）的新颖设计方法。通过弹簧质量模型定性地阐明了SMA网壳在不同状态和负载下的能量变化。为了优化SMA网壳的性能，采用非接触光驱动技术来诱导其形状转变。实验研究探索了网壳的变形响应、能量释放以及光功率密度之间的关系。结果表明，SMA网壳具有显著的跳跃能力，实现了60倍体长的跳跃高度和高达每秒300倍体长的起飞速度。此外，两个示例案例突出了网壳在非结构化地形中的应用潜力。本研究通过提供一种整合智能材料和先进结构的新设计方法，为小型化跳跃机构做出了贡献。
