Abstract: Measurements of impulsive forces and pressures by means of the elastic bar require that the effect of waves' dispersion in the bar on the sensor's output signal be corrected. The correction problem can be solved using deconvolution techniques. For this purpose it is necessary to determine the elastic bar's transfer functions. In this paper, an experimental method of determining the elastic bar's transfer functions in form of formulas is described, which can be used to reconstruct the input waveform. The method is based on: one-point measurement of the elastic strain waves propagating inside the bar, the spectral analysis of these waves and making use of the general solution of the equation of movement of the bar in the frequency domain. The determined transfer functions of the bar are used for impulsive strain waveform reconstruction by means of deconvolution in the frequency domain, and for the validity check of the reconstruction. The application of this method to the reconstruction of impulsive force waveforms generated by the mechanical impact of bodies is presented.
B I B L I O G R A F I A1. Gorham, D.A., "A numerical method for the correction of dispersion in pressure bar signals", J. Phys. E: Sci. Instrum., vol. 16, 1983, p.477-479
2. Follansbee, P.S.& Frantz, C., "Wave propagation in the split Hopkinson pressure bar", J. Eng. Mater. Technol., vol. 105, 1983, p.61-66
3. Gong, J.C.& Malvern, L.E.& Jenkins, D.A., "Dispersion investigation in the split Hopkinson pressure bar", J. Eng. Mat. Technol., vol. 112, 1990, p.309-314
4. Kaczmarek, Z., "Method for the correction of dispersive distortion in the output signal of a mechanical impulsive excitation sensor", Meas. Automatics Control, vol. 4, 2006, p.7-9, (in Polish)
5. Gorham, D.A.& Wu, X.I., "An empirical method for correcting dispersion in pressure bar measurements of impact stress", Meas. Sci. Technol., vol. 7, 1996, p.1227-1232
6. Kaczmarek, Z.& Drobnica, A., "A reconstruction method of impulsive pressure and force waveform by means of wavelet transform", Studies in Applied Electromagnetics and Mechanics 18 Nonlinear Electromagnetic System, 2000, pp. 417-420
7. Kaczmarek, Z.& Kaczmarek, C.& Nichoga, A., "A modified impulsive force and pressure sensor intended for waveform reconstruction purposes", IEEE Trans. Instrum. Meas., vol. 51, 1, 2002, p.102-106
8. Kaczmarek, Z., "A frequency-domain deconvolution approach for impact force waveform restoration with the use of one-point strain measurement", Metrol. Meas. Syst., vol. IX, 1, 2002, p.3-17
9. Bacon, C., "An experimental method for considering dispersion and attenuation in viscoelastic Hopkinson bar", Exp. Mech., vol. 38, 4, 1998, p.242-249
10. Lundberg, B.& Blanc, R.H., "Determination of mechanical material properties from the two-point response of an impacted linearly viscoelastic rod specimen", J. Sound Vibration, vol. 126, 1, 1988, p.97-108
11. Obraz, J., "Ultrasounds in Measuring Technique", 1983, (Chapter 1, pp 17-72, in Polish)
12. Bancroft, D., "The velocity of longitudinal waves in cylindrical bars", Phys. Rev., vol. 4, 1944, p.588-593 
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