3D-printed steel lattice with a twist mechanism promises tunable impact protection

A research team at the University of Glasgow, with support from the Polytechnic University of Marche, the University of L’Aquila, and Italy’s National Institute for Nuclear Physics, presents an additively manufactured metamaterial whose energy absorption varies solely through mechanical boundary conditions. At its core is a gyroid-based steel lattice that, under axial compression, transitions in a controlled manner into torsion. The goal is a component that can switch between stiff support and soft damping without the need for actuators, sensors, or fluidics.

Technically, the structure is based on a highly porous gyroid topology printed using a powder-bed process. The periodic architecture couples translation and rotation: when the component is compressed, it develops a corkscrew-like twist that distributes impact energy. Three boundary cases were investigated. With rotation blocked, the lattice showed the highest stiffness and the greatest specific energy absorption, measured at 15.36 J per gram of material. When rotation was released, stiffness and energy absorption dropped by about ten percent. If over-rotation was enforced, energy absorption decreased by roughly 33 percent. This enables the crash response to be tailored to the load case, installation space, and rebound behavior.

Professor Shanmugam Kumar of the University of Glasgow’s James Watt School of Engineering led the research, said: “The protective materials used in most vehicles today are static, designed for specific impact scenarios and unable to adapt to varying conditions. This study introduces adaptive twisting metamaterials as a new class of metamaterials that don’t require any complex electronics or hydraulics to adapt. Instead, they can adapt simply through mechanical control of rotation. When we apply compression, the gyroid lattice translates it into twist, and by changing the boundary conditions, we can tune the energy absorption characteristics. These materials can adapt and change their own characteristics depending on the impact type and severity to mitigate effects.

We believe the material could find applications in both automotive and aerospace safety in the future, providing a single new class of material capable of adapting to different needs as required. It could also support the development of novel forms of energy harvesting, by converting impacts into rotational kinetic energy.”

For validation, the researchers combined tests under high-rate impact loading and quasi-static deformation with finite-element simulations in a micropolar (Cosserat) continuum framework. Micro-CT imaging quantified load- and process-induced geometric deviations of the additively manufactured lattices, enabling close alignment between simulation and measurement. Relevant metrics such as axial stiffness, collapse stress, and dissipated energy were captured across the full twist range to derive a robust parameterization for component design.

Looking ahead, applications in passive protection systems for automotive and aerospace are conceivable. In addition, coupling compression and torsion opens avenues for energy recovery by converting impact work into rotational motion.