A numerical study of the crushing of thin-walled circular aluminum tubes has been carried out to investigate the crashworthiness behaviors under axial impact loading. These kinds of tubes are usually used in automobil...A numerical study of the crushing of thin-walled circular aluminum tubes has been carried out to investigate the crashworthiness behaviors under axial impact loading. These kinds of tubes are usually used in automobile and train structures to absorb the impact energy. Previous researches show that thin-walled circular tube has the highest energy absorption under axial impact amongst different structures. In this work, the crushing between two rigid flat plates and the tube rupture by 4 and 6 blades cutting tools is modeled with the help of ductile failure criterion using the numerical method. The tube material is aluminum EN AW-7108 T6 and its length and diameter are 300 mm and 50 ram, respectively. Using the artificial neural network （ANN）, the most important surfaces of energy absorption parameters, including the maximum displacement of the striker, the maximum axial force, the specific energy absorption and the crushing force efficiency in terms of impact velocity and tube thickness are obtained and compared to each other. The analyses show that the tube rupture by the 6 blades cutting tool has more energy absorption in comparison with others. Furthermore, the results demonstrate that tube cutting with the help of multi-blades cutting tools is more stable, controllable and predictable than tube folding.展开更多
Both Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys（mass fraction,%）were extruded at 380？C.Most of the（10^-10） crystal planes in the Mg-1Mn-3.5Y alloy are parallel to the normal direction,while most of the（10^-11）cryst...Both Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys（mass fraction,%）were extruded at 380？C.Most of the（10^-10） crystal planes in the Mg-1Mn-3.5Y alloy are parallel to the normal direction,while most of the（10^-11）crystal planes in the Mg-1Mn-1Y-2.5Nd alloy are parallel to the normal direction.The tensile tests at room temperature,100℃ and 200℃ show that the Mg-1Mn-3.5Y alloy exhibits higher yield strength,but lower elongation to failure as compared with the Mg-1Mn-1Y-2.5Nd alloy. These differences in the tensile mechanical properties between the two alloys are mainly attributed to their different texture types and amount and distribution of the Mg24Y5 precipitates.The serration flow behavior is observed in the Mg-1Mn-1Y-2.5Nd alloy at 200℃,but does not occur in the Mg-1Mn-3.5Y alloy.The Mg-1Mn-3.5Y alloy shows the cleavage fracture mode,while the Mg-1Mn-1Y-2.5Nd alloy exhibits the dimple fracture mode.展开更多
文摘A numerical study of the crushing of thin-walled circular aluminum tubes has been carried out to investigate the crashworthiness behaviors under axial impact loading. These kinds of tubes are usually used in automobile and train structures to absorb the impact energy. Previous researches show that thin-walled circular tube has the highest energy absorption under axial impact amongst different structures. In this work, the crushing between two rigid flat plates and the tube rupture by 4 and 6 blades cutting tools is modeled with the help of ductile failure criterion using the numerical method. The tube material is aluminum EN AW-7108 T6 and its length and diameter are 300 mm and 50 ram, respectively. Using the artificial neural network （ANN）, the most important surfaces of energy absorption parameters, including the maximum displacement of the striker, the maximum axial force, the specific energy absorption and the crushing force efficiency in terms of impact velocity and tube thickness are obtained and compared to each other. The analyses show that the tube rupture by the 6 blades cutting tool has more energy absorption in comparison with others. Furthermore, the results demonstrate that tube cutting with the help of multi-blades cutting tools is more stable, controllable and predictable than tube folding.
基金Project(50771049)supported by the National Natural Science Foundation of ChinaProject(2004CB619301)supported by the National Basic Research Program of China
文摘Both Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys（mass fraction,%）were extruded at 380？C.Most of the（10^-10） crystal planes in the Mg-1Mn-3.5Y alloy are parallel to the normal direction,while most of the（10^-11）crystal planes in the Mg-1Mn-1Y-2.5Nd alloy are parallel to the normal direction.The tensile tests at room temperature,100℃ and 200℃ show that the Mg-1Mn-3.5Y alloy exhibits higher yield strength,but lower elongation to failure as compared with the Mg-1Mn-1Y-2.5Nd alloy. These differences in the tensile mechanical properties between the two alloys are mainly attributed to their different texture types and amount and distribution of the Mg24Y5 precipitates.The serration flow behavior is observed in the Mg-1Mn-1Y-2.5Nd alloy at 200℃,but does not occur in the Mg-1Mn-3.5Y alloy.The Mg-1Mn-3.5Y alloy shows the cleavage fracture mode,while the Mg-1Mn-1Y-2.5Nd alloy exhibits the dimple fracture mode.
