An Investigation on Dynamic Properties of Aluminium Alloy Foam Using Modified Large Scale SHPB Based on Dispersion Correction

摘要

The dynamic properties of aluminium alloy foam were investigated by using split Hopkinson pressure bar (SHPB) with diameter of 40 mm. The aluminium alloy pressure bar and pulse shape technique were used to modify the traditional SHPB due to the low impedance of aluminium alloy foam. Wave dispersion correction on the aluminium alloy pressure bar was studied by Fourier series. And the finite element numerical simulation was also performed to demonstrate and validate the dispersion correction results by Fourier series method. The reflected and transmitted wave measured in SHPB experiments were corrected by the backward Fourier series expansion. The results show that there is an obvious dispersion for the stress wave travelling in the 40 mm aluminium alloy pressure bar. The dispersion correction reduces the oscillations in reflected and transmitted stress waves and stress-strain curves. And the corrected stress-strain curves of the aluminium alloy foam at various strain rates were obtained. The effects of the stain rate and strain on the dynamic properties of the aluminium foam were also discussed.