Post-yield softening of bending-dominated metal metamaterials

Post-yield softening (PYS) plays an important role in guiding the design of high-performance energy-absorbing lattice materials. PYS is usually restricted to lattice materials that are stretching dominated according to the Gibson-Ashby model. Contrary to this long-held assumption, this work shows that PYS can also occur in various bending-dominated Ti-6Al-4V lattices with increasing relative density. The underlying mechanism for this unusual property is elucidated using the Timoshenko beam theory. It is attributed to the increase in stretching and shear deformation with increasing relative density, thereby increasing the tendency towards PYS. The finding of this work extends perspectives on PYS for the design of high-performance energy-absorbing lattice materials.

Automated summary

Post-yield softening (PYS) is an important factor in guiding the design of high-performance energy-absorbing lattice materials. Contrary to previous assumptions, this study shows that PYS can occur in bending-dominated Ti-6Al-4V lattices with increasing relative density. The underlying mechanism is explained by the increase in stretching and shear deformation as relative density increases, leading to a higher tendency towards PYS. This finding expands perspectives on PYS for the design of high-performance energy-absorbing lattice materials.