Experimental Study And Theoretical Analysis On The Static Compressive Of Foamed Aluminum Alloys And Their Sandwich Panels

Metal foams used as energy absorption or impact protection devices are often subjected to impact loads, so understanding the static compressive properties are attracting more eyes. Investigating on what and how their static behaviors are influenced is of practical meaning to the application of metal foams. In this paper the influencies of the cell size, sample height, strain rate and heat treatment on the mechanical behavior and deformation characters of aluminum alloy foams are studied systematically in experiment DNS series electronic pressureniversal testing combined with theoretical analysis. The reserches are outlined as following:(1) The influence of cell size on the static compressive properties and energy absorption capacities of aluminum alloy foam.The compressive tests were conducted on aluminum alloy foam with different cell size.It is found that there existed significant effects of cell size on the static compressive properties. The metal foams with 1.5mm cell diameter have the best properties for same size sample.(2) The influence of sample stacle on the static compressive properties and energy absorption capacities of aluminum alloy foam on samples with different height and on samples stacked. Compressive tests were conducted comparing the results of stacked samples and not-stacked ones with same height, following conclusion can be drawn:1) Sample height did not influence the plateau strength of the aluminum alloy foam. 2) Samples stacked have the same static compressive properties and energy absorption capacties as the no-stacked ones.(3) The influence of strain rate on the static compressive properties and energy absorption capacities of aluminum alloy foamsCompressive tests were performed under different strain rates on same samples.The initial strain rates were 1.0×10-3s-1,1.6×10-3s-1,2.5×10-3s-1 respectively. It is found that the plateau strength is not sensitive to the initial strain rate,which is between 1.0×10-3s-1～2.5×10-3s-1 range.(4) The effects of heat treatment on the static compressive properties and energy absorption of aluminum alloy foamHeat treatment process has been applied to aluminum alloy foams. Heat treated samples were compressed use DNS universal testing machine.The results showed that:heat treatment could increase the yield strength of aluminum alloy foam and did not affect its energy absorption efficiency.(5) The static compressive properties of aluminum alloy foam sandwich panelsFor making aluminum alloy foam materials sandwich panels, aluminum face sheet of 0.5 mm,0.8 mm,1.0 mm thickness and iron face sheet of 0.5 mm thickness were used respectively.Following results are found by comparing the compressive experimental results of sandwich panels with those of pure foam: 1) Sandwiched panels showed higher compressive mechanical properties.2) The length of plastic plateau is corelated with the thickness ratio of the face sheet to foam sheet. And there exists sensitive critical valueλ*. 3) Sandwiched panels with iron face sheets has a smaller sensitive critical valueλ* than those with aluminum face sheets.