基于高速摄影实验的小提琴琴弦三维振动特性研究

摘要

The interaction mechanism between violin bow and string is very complicated due to the stick-slip friction action,and it forms a complex vibration system.The vibration characteristics of violin strings were studied through theoretical analysis and experimental method.In order to measure the three dimensional vibration configuration of strings, an optical noncontact measurement system based on high-speed photography was designed.Some color marks were set on string and then the vibration images were got when bowing or plucking the violin string.The string vibration characteristics of two different action mechanisms of plucking and bowing string were investigated,including vibration displacement, velocity and space trajectory of the mark points on string.By comparing the displacement curves of the different points on string,the variety of the ratio of positive process time to negative process time of vibration sawtooth waveform were studied,and the formation process of vibration enveloping curve was observed.The factors affecting the vibration amplitude of violin string were analyzed.%小提琴弓弦之间的相互作用机理非常复杂，由于粘滑摩擦作用形成一个复杂的振动系统。通过理论分析和实验方法，对琴弦的振动特性进行了研究。为了测量琴弦的三维振动情况，设计一个基于高速摄影的非接触式光学测量系统，通过在琴弦上设置一些颜色标定点，拍摄拉、拨弦时琴弦的振动图像，得到两种不同机制的琴弦振动特征，包括振动位移、速度及弦上标定点的空间运动轨迹等。对弦上不同位置点的位移曲线进行了比较，研究其振动锯齿波的正、逆程时间比值变化和振动包络线的形成过程，最后分析了影响弦振幅的因素。