Accurate finite element simulation and experimental study of elastic wave propagation in a long cylinder under impact loading

作者：Idesman A V^*; Mates S P

来源：International Journal of Impact Engineering, 2014, 71: 1-16.

DOI：10.1016/j.ijimpeng.2014.04.002

• Elastic waves
• Impact loading
• Hopkinson bar
• Finite elements
• Spurious oscillations

For the first time, detailed accurate numerical solutions for elastic wave propagation in a long axisymmetric elastic bar under impact loading are obtained using the new finite element technique proposed in our recent papers. In contrast to known numerical techniques, the new numerical approach quantifies and removes spurious high-frequency oscillations which may invalidate numerical results in impact loading simulations. The comparison of the accurate experimental results for the impact of striker and incident bars with the corresponding accurate numerical results allows us to explain some details of elastic wave propagation in long bars. For example, due to the absence of very high frequencies in the obtained experimental results, the mathematical formulation of the problem should include physical damping for the corresponding range of high frequencies. This range can be defined by the filtering stage of the new approach in terms of the number of finite elements along the radial direction of the bar. By the variation of this number we can fit the experimental curves with the numerical results obtained by the new numerical technique. However, for the accurate numerical solution of the impact problem with zero physical damping, the number of elements in the radial direction should be large. By the comparison of the numerical and experimental data, we can accurately determine the longitudinal wave velocity from experiments. The accurate numerical solutions also allow the analysis of the uniformity of the different strain and velocity components across the radius at different distances from the impact face. The validity of some assumptions used in the 1-D theory for wave propagation in long bars is also checked by the use of the accurate numerical solution. We have also shown that at the elastic impact the known dispersion-correction technique used for the description of the shape of the wave pulse at different locations along the axisymmetric bar is inaccurate for the prediction of pulses close to the impact face.

• 出版日期2014-9