Transient Wave Mechanism from Impact Machinery

This paper outlines a transient wave mechanism from an impact machinery such as punch press via computational and experimental methods. Results from the boundary element method to predict the transient acoustic field are compared with experiment by use of the fiber-optic surface acoustic intensity probe. The computational method combines an explicit and implicit methods to enhance the numerical stability and accuracy. The fiber-optic surface acoustic intensity probe which combines optical fibers and microphone will be discussed to illustrate the validity of the experimental method and hence numerical results. The improvement of the acoustic intensity probe performance will also be discussed to eliminate the phase error at higher frequency measurement and to increase the sensitivity and linearity. The comparison of the results will be described to demonstrate the capability and accuracy of the methods to identify the transient noise source generated from the impact noise. The importance of the non-resonant frequency contents in the transient wave mechanism will be discussed through the simulated frequency responses where resonant components have been eliminated.