海棠果树动力学特性的研究

Study on the Dynamic Characteristics of Begonia Fruit Trees

研究了果树在外界载荷作用下,果树形态结构(果枝直径,分叉角度)对能量传播速度及能量在分叉位置处分流情况的影响。选择1棵"Y"型果树进行室内试验,激振载荷选择冲击载荷和正弦连续振动载荷。在冲击试验中,得出各测点加速度曲线第1次出现波峰或波谷的时间差,从而计算出能量从某一测点传递到相邻测点的传播速度;在连续试验中,对得到的加速度信号进行曲线拟合,将得到的加速度拟合函数进行积分得到速度函数,进而求出果枝上各测点的动能,将这部分动能视为振动传递到各测点的能量。根据得出的拟合函数可知:在正弦激振载荷作用下,果枝上的加速度信号呈正弦函数分布,并且激振频率与果枝加速度频率几乎一致。研究表明:能量在主干上的传播速度大于在枝干上的传播速度,分叉角度越小,能量传播速度越大;能量在流经分叉点处时,产生分流,能量更多地流向枝干直径大的一侧。

The effect of fruit tree morphology （branch diameter, branching angle） on the energy propagation velocity and energy shunting at the bifurcated position was studied under the external load.Select a ＆quot;Y＆quot; type fruit trees for indoor test, excitation load selection shock load and sinusoidal continuous vibration load.In the impact test, the acceleration curve of each measuring point for the first time the peak or trough the time difference to calculate the energy transfer from a measuring point to the adjacent measuring point of the propagation velocity;continuous test, the resulting acceleration Then the kinetic energy of each measuring point on the fruiting branch is obtained and the kinetic energy is regarded as the energy transmitted to the measuring points by the vibration.According to the obtained fitting function, the acceleration signal of the fruiting branch is distributed sinusoidally under the sinusoidal excitation load, and the excitation frequency is almost the same as the acceleration frequency of the fruit branch.The propagation speed of energy on the trunk is larger than that on the trunk.The smaller the branching angle is, the higher the energy propagation speed is.Energy flows through the bifurcation point, resulting in shunting, energy flow to the larger diameter of the side of the trunk.