Measuring the frequency response of the honeybee thorax
Measuring the frequency response of the honeybee thorax
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DOI：
10.1088/1748-3190/ab835b
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发表时间：
2020-07-01
影响因子：
3.4
通讯作者：
Jankauski, Mark A.
中科院分区：
文献类型：
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作者：
Jankauski, Mark A.
具有异步飞行肌肉的昆虫被认为是以其胸翼系统的有效基频拍打。以这种方式拍动利用胸部的自然弹性来减少飞行的能量需求。然而，据我们所知，昆虫翅膀-肌肉-胸部系统的基频尚未被测量。在这里，我们测量了蜜蜂胸的线性频率响应函数（FRF）的平衡状态，以确定其基本频率。频率响应函数将输入力与昆虫背板处的输出加速度相关联，并且通过机械振动振动器组件获取。当压缩50 μ m时，所有受试者的胸部基频平均值比报道的翅拍频率高约50%。我们怀疑，由于边界条件和死后肌肉硬化，实验中测得的基频高于飞行中测得的基频。接下来，我们压缩胸腔之间的100-300 μ m的50 μ m的间隔，以评估几何修改的基本频率的灵敏度。对于所考虑的所有标本，胸部基频增加几乎单调的压缩水平。这意味着当受到大位移时，胸部表现为非线性硬化弹簧，我们通过静态力-位移测试证实了这一点。虽然几乎没有证据表明昆虫在飞行期间利用这种非线性，但可以通过小型谐振型扑翼微型飞行器来模拟硬化特性，以增加扑动频率带宽。总之，通过本工作建立的方法提供了进一步的动力学研究昆虫胸向前推进的基础。
Insects with asynchronous flight muscles are believed to flap at the effective fundamental frequency of their thorax-wing system. Flapping in this manner leverages the natural elasticity of the thorax to reduce the energetic requirements of flight. However, to the best of our knowledge, the fundamental frequency of the insect wing-muscle-thorax system has not been measured. Here, we measure the linear frequency response function (FRF) of honeybee Apis mellifera thoraxes about their equilibrium state in order to determine their fundamental frequencies. FRFs relate the input force to output acceleration at the insect tergum and are acquired via a mechanical vibration shaker assembly. When compressed 50 mu m, the thorax fundamental frequency averaged across all subjects was about 50% higher than reported wingbeat frequencies. We suspect that the measured fundamental frequencies are higher in the experiment than during flight due to boundary conditions and posthumous muscle stiffening. Next, we compress the thorax between 100-300 mu m in 50 mu m intervals to assess the sensitivity of the fundamental frequency to geometric modifications. For all specimens considered, the thorax fundamental frequency increased nearly monotonically with respect to level of compression. This implies that the thorax behaves as a nonlinear hardening spring when subject to large displacements, which we confirmed via static force-displacement testing. While there is little evidence that insects utilize this non-linearity during flight, the hardening characteristic may be emulated by small resonant-type flapping wing micro air vehicles to increase flapping frequency bandwidth. Overall, methods established through this work provide a foundation for further dynamical studies on insect thoraxes moving forward.