Torsional Mechanical Behavior of TPMS Porous Structures: Experimental Insights on Diamond, Gyroid, and Schwarz Primitive Designs

ABSTRACT Triply periodic minimal surface (TPMS) porous structures exhibit significant potential for industrial applications owing to their high surface area, lightweight, and tunable mechanical properties. This work explores the torsional behavior of three typical TPMS porous structures, including diamond, gyroid, and Schwarz primitive types. Monotonic torsion tests show that the torsional resistance increases with relative density. Under symmetric cyclic torsional loading, the normalized torque amplitude decreases with increasing cycles, whereas failure cycles decrease and dissipated energy increases with higher strain amplitudes. Once the strain exceeds the elastic threshold, the torque amplitude initially drops sharply and then gradually declines until fracture occurs. In asymmetric cyclic torsion tests, the fracture morphology under asymmetric torsion remains consistent with that observed under monotonic torsion. These findings contribute to a deeper understanding of the mechanical reliability of TPMS porous structures and offer guidance for their structural optimization in engineering applications.