Author/Authors :
Emadi, Mina Textile Engineering Department - Yazd University, Yazd, Iran - and Center of Excellence for Machine Vision in Textile and Apparel Industry - Yazd University, Yazd, Iran , Payvandy, Pedram Textile Engineering Department - Yazd University, Yazd, Iran - and Center of Excellence for Machine Vision in Textile and Apparel Industry - Yazd University, Yazd, Iran , Tavanaie, Mohammad Ali Textile Engineering Department - Amirkabir University of Technology - Tehran, Iran - and Center of Excellence for Machine Vision in Textile and Apparel Industry - Yazd University, Yazd, Iran , Jalili, Mohammad Mahdi Mechanical Engineering Department - Yazd University, Yazd, Iran
Abstract :
The main aim of this study is to obtain a detailed information about textile string vibration and the effect of physical properties changes on it. This is based on the fact that
modal parameters are the functions of physical properties.
Video cameras propose the unique capability of collecting
high density spatial data from a distant view and supply a
reliable method for measuring vibrations and displacements
in structures. They could be employed as inspection sensors
because of their normal use, ease, and low cost. In this
research, some laboratory equipment with a high-speed digital
camera was designed to measure the vibration behavior of
polypropylene monofilaments. The vibration was recorded by
the high-speed camera at all the points of the string, and video
processing was done to extract the free decays. The natural
frequency, amplitude and phase were obtained by the Fourier
series. The logarithmic decrement and the damping coefficient
for monofilaments were calculated. The experimental results
were compared to the results of a theoretical model for a plucked string with viscous damping, and the vibration
properties of monofilaments were obtained. As the results
showed, the theoretical model could successfully predict the
vibration behavior of the filaments with error less than 23%.
The trend of changes in the monofilament physical properties
was easily specified based on the trend of the variations in the
damping coefficient and the natural frequency. It was found
that an increase in the monofilament linear density would cause a decrease in the damping coefficient and its natural frequency.
Keywords :
vibration analysis , monofilament , high-speed camera , computer vision
