Dynamic compression behavior of various kinds of polygonal tubular structures with ribs are investigated. Square hollow structures and that with rib reinforcement of aluminum extrusions are in dynamic axial compression, using a drop hammer. Numerical simulation was also conducted for the wider variety of cross-sectional shapes and reinforcements. The effect of the axial length, cross-sectional shape and reinforcing rib arrangement on the deformation behavior were investigated. Comparable compressive force was obtained when the cross-sectional area of the structure is similar, even if the number of edges in cross-section increases from four (square) to eight. Rib reinforcement is very effective for the improvement of the crush or energy absorbing performance. Deformation behavior was successfully predicted by the numerical simulation. Numerical simulation of the compression of the various polygonal tubular structures with radial ribs was also carried out. The number of radial ribs in cross-section of the polygonal hollow structure has a positive relationship to the deformation constraint at corners and the torsional rigidity, consequently, the crush resistance increased.

It is known in cold rolled 3104 aluminum alloy sheets that ears on a cup are formed by deep drawing in 0° and 180° against the rolling direction. Previous reports discussed the relationship between crystallographic texture on original sheet and the ears, however, significant correlation wasn’t necessarily observed between anisotropy of the mechanical property and the ears. In order to know the mechanism of ear forming by deep drawing, texture development by deep drawing should be considered. In the present work, development of deformation texture in cold rolled 3104 aluminum alloy sheets by deep drawing was measured by X-ray diffraction method and then analyzed. Major orientations found in the deformation texture by deep drawing were similar to rolling texture, however, intensities of the Goss and Cu components were especially increased. Lattice rotation by deep drawing was estimated by analyzing orientation distribution function (ODF) and the crystallographic mechanism of the texture development was discussed.

In this study, the effects of impurities and processing conditions on the thermal stability of substructures formed via hot deformation were investigated using a plane strain compression (PSC) test. Two types of Al–1%Mn alloys were prepared. One of the alloys had a low content of silicon and iron owing to the use of pure aluminum bare metal (4N-1Mn alloy). The other was cast by using A1050 alloy (1050-1Mn alloy). The PSC tests were performed between 300 and 500°C and were followed by annealing at 500°C for 120 s in a salt bath. After the salt bath treatment, the 4N-1Mn alloys exhibited a recrystallized structure, whereas the 1050-1Mn alloys retained their fiber structure. Although the 4N-1Mn alloys exhibited a small increase in conductivity after the PSC test, the conductivity of the 1050-1Mn alloys showed an apparent increase. The synchrotron radiation analysis confirmed Al–Mn–Si precipitations in the compressed 1050-1Mn alloys. These precipitations could be the reason for the change in conductivity in the compressed 1050-1Mn alloys. Precipitations were barely observed for the compressed 4N-1Mn alloys, and small precipitations formed during hot deformation seemed to affect the formation of the thermal stabilized substructures. In addition, the study results showed that impurities, such as silicon, contribute to precipitation during hot deformation.