A Pulse Shaper Model for Hopkinson Pressure Bars

doi:10.12382/bgxb.2022.0517

Abstract

Abstract:

Adding a pulse shaper for Hopkinson bars is an important method to adjust the profile of incident pulses and accurately measure the dynamic mechanical properties of explosives. To predict the complete profile of incident pulses after incorporating the pulse shaper, the wave propagation process in the striker-pulse shaper-incident bar system is analyzed based on the stress wave theory. A unified governing equation predicting the loading-unloading process of pulse shapers is obtained using the superposition principle of waves. Consequently, a general pulse shaper model is developed. The one-dimensional stress-strain relationship of T2 pure copper is obtained by using Hopkinson pressure bar and pulse shaper experiments. The model predicts the profile of incident pulses of single pulse shaper and dual pulse shaper experiments, and analyzes the deformation characteristics of the pulse shaper under various conditions. The results show that the pulse shaper model is able to predict the complete profile of incident pulses, including the unloading range. The profile of incident pulses predicted by the model is in good agreement with the experimental results, indicating the validity of the model and the high accuracy of the calibrated parameters.

Key words: Hopkinson pressure bars, stress waves, pulse shaper model, profile of incident pulses

MIAO Feichao, ZHANG Xiangrong, LI Dongwei, JIANG Tao, ZHOU Lin. A Pulse Shaper Model for Hopkinson Pressure Bars[J]. Acta Armamentarii, 2023, 44(7): 1978-1984.

Figures/Tables 9

Fig.1 Schematic diagram of a single pulse shaper

Fig.2 Schematic diagram of stress wave propagation in the striker-pulse shaper-incident bar system

Fig.3 Schematic diagram of a dual pulse shaper

Table 1 Material parameters of the Hopkinson bar

材料	密度/ (kg·m^-3)	声速/ (m·s^-1)	弹性模量/ GPa
马氏体时效钢	8000	5000	200

Fig.4 True stress-engineering strain relationship of T2 pure copper

Fig.5 Comparison of the profiles predicted by MPS and the experimental profile under two different conditions

Fig.6 Changes in deformation degree of the pulse shaper with time

Fig.7 Comparison of the profiles predicted by MPS and the experimental profile[17] using a dual pulse shaper

Fig.8 Particle velocity histories on the surfaces of the copper/steel pulse shapers

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