Dispersion correction in split-Hopkinson pressure bar: theoretical and experimental analysis
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The paper presents experimental and mathematical analysis of the dispersion effect of pulses, which propagate along an elastic bar whose cross section has a finite radius. In some cases, dispersion can influence significantly the interpretation of the experimental data, obtained in experimental schemes, which are based on using measuring bars for investigation material behavior at high strain rates (the split-Hopkinson pressure bar method and its modifications). Solutions for the Pochhammer–Chree equation are obtained for various measuring bars used in experimental setups in the Research Institute for Mechanics of Lobachevsky State University of Nizhny Novgorod. The procedure of pulse shift accounting for dispersion has been implemented and tested on the basis of our experimental data and the data available in the existing scientific literature. This procedure was employed to analyze the influence of pulse shape on the degree of its change in shape during its propagation along a measuring bar. It is shown how the procedure of dispersion shift improves the quality of interpretation of primary experimental data for some materials.
KeywordsThe Kolsky method Measuring bar Dispersion Wave number Experiment Deformation Frequency Frequency equation Strain pulse
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The theoretical part of work was carried out by a Grant from the Russian Science Foundation (Project No. 17-79-20161). The experimental part of work was done in the frame of the state task of the Ministry of Education and Science of the Russian Federation No. 9.6109.2017/6.7.
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