Measurement of impact load by using an inverse analysis technique. Comparison of methods for estimating the transfer function and its application to the instrumented Charpy impact test.

Abstract

This paper is concerned with a method for measuring an impact load acting on a body of arbitrary shape. The impact load is determined from the strain response of the body by the deconvolution procedure which is performed in the frequency domain by using Laplace transformation. The transfer function is estimated from the result of the calibration experiment. The deconvolution is one of the ill-posed problems, and it is usually difficult to obtain a good result. In particular, high- frequency noise involved in the measured signal is often expanded to obscure the result. For this problem, we used five estimators of the transfer function and investigated which of them gives the most suitable transfer function for the deconvolution of experimental data. The efficiency of the method is demonstrated by applying it to the instrumentation of the Charpy impact testing machine.