Investigation On Compression And Bending Behavior Of Tubes Filled With Open-cell Aluminum Foam

Metallic foams are ultralight materials which possess high specific strength and energy absorption capacity. The metallic sandwich structure material is a new kind of ultralight structural and functional material which is prepared by filling metallic foams core into thin-walled structure. The mechanical behaviors and the deformation failure of sandwich structure have become one of the research hotspots in the material science, mechanics and other fields.In this paper, the aluminum foam-filled tubes are prepared by filling open-cell aluminum foams into thin-walled tubes. The open-cell aluminum foams are prepared by means of infiltrating process. The influence of the structural characteristic parameters both of the aluminum foam and the hollow tube on mechanical behaviors, energy absorption and yield behavior of the aluminum foam-filled tubes are explored. The main parameters of the samples are the relative density and pore diameter of the foam ranging form 0.399～0.524and 0.65~2.3mm respectively. The foam filled cylindrical tube diameter thickness ratio is between 5~30.4, and the foam-filled square tubes have the thickness width ratio (t/b) ranging form 0.012~0.032.Firstly, the static compression experiments have been conducted to investigate the compressive mechanical behavior of the circularity 6063 aluminum tubes filled with aluminum foams, The results show that the compressive load-displacement curves of aluminum tubes with foam filler exhibit a distinct characteristic of three deformation regions, i.e. elasticity region,serrated plastic plateau region and densification region. The factors such as the diameter thickness ratio of aluminum tube, the density and property of aluminum foam have remarkable effect on the mean crushing load and energy absorption characteristics of the foam-filled tube. Additionally, the compressive deformation pattern of the aluminum tube is also modified by the aluminum foam core, as compared with the non-filled tube. The wall of the tube with foam filler just folded outward during compression deformation.Secondly, the quasi-static three-point bending behavior of square 202 stainless steel tubes filled with aluminum foams is producted. The influence of aluminum foam relative density, t/b ratio and partially foam filled on bending behavior of the foam-filled tubes are mainly studied. The experimental results showed that the foams filler changes the local deformation mode of the tube, causes localized folding to propagate to the adjacent sections, and forces the tubes to form more plastic hinge lines, shorts the folding length. Therefore the foam filling improves the bending resistance of stainless steel tubes. Meanwhile,t/b ratio is the mainly influence parameter for deformation mode of the tube.Finally, It is also indicated that the length of the foam filling must reach a certain length, just the effective foam length L f ,eff, can the foam-filled tubes maintain higher crushing resistance under large scale rotation. The effective foam length L f ,eff offers significant reduction of the foam weight and should be used as a guideline for designing the ultralight foam-filled tubes.