University of Novi Sad, Faculty of Technical Sciences, 21000, Novi Sad, Serbia.
University of Novi Sad, Faculty of Agriculture, 21000, Novi Sad, Serbia.
Sci Rep. 2018 Jun 4;8(1):8558. doi: 10.1038/s41598-018-26726-5.
This study presents quantitative and qualitative insights into the analysis of data obtained by tracking the motion of reflective markers arranged along the trunk of a pole-like potted tree, which was recorded by a state-of-the-art infrared motion-tracking system. The experimental results showed in-plane damped trajectories of the markers with lateral displacements, i.e. out-of-plane vibrations of the tree under consideration. To explain such response and to determine the corresponding oscillatory characteristics, a completely new and original utilisation of the recorded in-plane damped trajectories is presented. The quantitative insight gained is based on the mechanical model that consists of two orthogonal springs and dampers placed in the plane where the motion takes place, and it is then directed towards the determination of the characteristics of the related orthogonal oscillations: two natural frequencies, the position of the principal axes to which they correspond, and two damping ratios. The qualitative insight gained involves analysing the shape and narrowness of the trajectory to assess how close-valued two natural frequencies are, and how small the overall damping is. The quantitative and qualitative methodologies presented herein are seen as beneficial for arboriculture, forestry and botany, but given the fact that orthogonal oscillations appears in many natural and engineering systems, they are also expected to be useful for specialists in other fields of science and engineering as well.
本研究通过使用最先进的红外运动跟踪系统对沿杆状盆栽树树干排列的反光标记的运动进行跟踪所获得的数据进行了定量和定性分析。实验结果表明，标记具有平面阻尼轨迹，同时伴随着横向位移，即所研究树木的面外振动。为了解释这种响应并确定相应的振荡特性，提出了一种全新的、原始的利用记录的平面阻尼轨迹的方法。所获得的定量洞察力基于由两个正交弹簧和阻尼器组成的机械模型，这些弹簧和阻尼器放置在运动发生的平面上，然后用于确定相关正交振动的特性：两个固有频率、与它们相对应的主轴位置以及两个阻尼比。所获得的定性洞察力涉及分析轨迹的形状和狭窄程度，以评估两个固有频率的接近程度以及整体阻尼的大小。本文提出的定量和定性方法被认为对树木栽培学、林业和植物学有益，但由于正交振动出现在许多自然和工程系统中，因此也有望对其他科学和工程领域的专家有用。
