2024 Volume 65 Issue 763 Pages 116-122
Ultralight porous metals are attractive for reducing car weight owing to their high specific rigidity and excellent impact energy absorption. However, several problems remain with their application as car parts, such as inhomogeneity, low performance controllability, high production costs and low tensile strength. To solve these problems, a new porous metal with a lattice structure was proposed. Arranged holes, which result in ridge intersections, are cut off from a thin metal sheet by punching in the first process, and ridges are formed along a line of holes by U- shape bending in the second process. Next, the components, which are the metal sheets formed in these processes, are stacked and finally spot-welded. Since the components are mass-produced by progressive press machines with dies, a homogeneous porous structure can be fabricated inexpensively. The performance of the structure can be easily controlled by changing the metal sheet thickness and ridge shape. Tensile and bending strengths are high because there are no extremely thin cell walls. Compression and bending tests were carried out to confirm the compressive plateau stress, compressive energy absorbing efficiency and bending load-stroke relation of the material.
