Ge Dali, Dai Yuntong, Li Kai
School of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China.
Institute of Advanced Technology, University of Science and Technology of China, Hefei 230001, China.
Polymers (Basel). 2023 Aug 3;15(15):3294. doi: 10.3390/polym15153294.
Self-oscillation is the autonomous maintenance of continuous periodic motion through energy absorption from non-periodic external stimuli, making it particularly attractive for fabricating soft robots, energy-absorbing devices, mass transport devices, and so on. Inspired by the self-oscillating system that presents high degrees of freedom and diverse complex oscillatory motions, we created a self-oscillating helical spring oscillator with combined tension and torsion under steady illumination, among which a mass block and a liquid crystal elastomer (LCE) helical spring made with LCE wire are included. Considering the well-established helical spring model and the dynamic LCE model, a nonlinear dynamic model of the LCE helical spring oscillator under steady illumination is proposed. From numerical calculation, the helical spring oscillator upon exposure to steady illumination possesses two motion regimes, which are the static regime and the self-tension-torsion regime. Contraction of the LCE wire under illumination is necessary to generate the self-tension-torsion of the helical spring oscillator, with its continuous periodic motion being maintained by the mutual balance between light energy input and damping dissipation. Additionally, the critical conditions for triggering the self-tension-torsion, as well as the vital system parameters affecting its frequencies and amplitudes of the translation and the rotation, were investigated in detail. This self-tension-torsion helical spring oscillator is unique in its customizable mechanical properties via its structural design, small material strain but large structural displacement, and ease of manufacture. We envision a future of novel designs for soft robotics, energy harvesters, active machinery, and so on.
自振荡是通过从非周期性外部刺激中吸收能量来自主维持连续周期性运动，这使得它在制造软体机器人、能量吸收装置、物质传输装置等方面具有特别的吸引力。受呈现高度自由度和多样复杂振荡运动的自振荡系统启发，我们在稳定光照下创建了一种具有拉伸和扭转组合的自振荡螺旋弹簧振荡器，其中包括一个质量块和一个由液晶弹性体（LCE）丝制成的LCE螺旋弹簧。考虑到成熟的螺旋弹簧模型和动态LCE模型，提出了稳定光照下LCE螺旋弹簧振荡器的非线性动力学模型。通过数值计算，光照下的螺旋弹簧振荡器具有两种运动状态，即静态状态和自拉伸 - 扭转状态。LCE丝在光照下收缩对于产生螺旋弹簧振荡器的自拉伸 - 扭转是必要的，其连续周期性运动通过光能输入和阻尼耗散之间的相互平衡得以维持。此外，还详细研究了触发自拉伸 - 扭转的临界条件以及影响其平移和旋转频率与振幅的关键系统参数。这种自拉伸 - 扭转螺旋弹簧振荡器在通过结构设计实现可定制机械性能、小材料应变但大结构位移以及易于制造方面具有独特性。我们设想了软体机器人技术、能量收集器、主动机械等新颖设计的未来。
