Investigation On The Dynamic Compressive Behavior And Energy Absorption Properties Of Aluminium-silicon Foam

Metal foam is a kind of light-weighted porous material which contains a largenumber of holes. As a kind of functional material, it has properties of light weight,high strength, sound absorption and energy absorption capabilities, making it widelyused in car, aerospace and construction fields etc. For example, car’s bumper of foamaluminum, foam metal materials used on spacecraft to absorb energy and used forprotection packing and so on. All these applications are related to deformation anddynamic impact load. Therefore, it is of scientific research significance andengineering application value to investigate on the dynamic characteristics of metalfoam so as to provide reference for material manufacturing and engineeringapplication. In this dissertation, the dynamic mechanical properties ofaluminium-silicon foam are investigated by using split Hopkinson pressure bar(SHPB). Compared with the quasi-static compressive results, the effect of the strainrate on the compressive strength and absorption efficiency is analyzed.First of all, techniques and equipment of the experiment are improved forlow-impedance aluminium-silicon foam based on traditional SHPB. LC4aluminumalloy pressure bar and the semiconductor strain gauge are employed to ensure thereliability of the experimental results. Using the revised SHPB, the stress waves areobtained at different strain rates.Based on the theoretical solution about the stress wave propagation in acylindrical bar and combining the Fourier transform, a program for analyzingdispersion in the cylindrical bar is developed. The validity of the program is checkedby finite element method. The influence of the physical parameters and geometricparameters of the bar over the dispersion for wave propagation in the cylindrical baris studied. According to LC4aluminum alloy pressure bar with diameter of40mm,the stress waves obtained in the experiment are revised to lower the inaccuracy of theresults, the effect of stress wave dispersion to the curves is discussed.Finally, according to the principle of SHPB, the stress-strain curves arecalculated using the revised stress waves. The quasi-static compress ofaluminium-silicon foam is also carried out. Combined the phenomenon in theexperiment, the collapse mechanism, the energy absorption efficiency and idealityenergy absorption efficiency of the aluminium silicon foam at various strain rates are analyzed. The results show that, the strain rate has an obvious effect on the flow stressof the aluminium–silicon and aluminium-silicon foam is good energy absorbingmaterial.