Characterisation of an Additively Manufactured 3D Cross-Based Fractal Structure for Impact Energy Absorption

Designers propose using high-performance materials or cellular and bio-inspired structures in components with high strength-to-weight ratios, high heat transfer capacity, and energy absorption. An example is fractal geometries, which show highly complex 3D geometries that are unfeasible using conventional manufacturing processes. The work investigates the energy absorption performances of a 3D cross-based fractal structure (3D-CFS). The geometry is inspired by the mathematical 3D Greek cross geometry and designed for production using Additive Manufacturing (AM) powder bed fusion processes for polymers (PBF). The mechanical properties of Polyamide (PA12) and Thermoplastic Polyurethane (TPU) 3D-CFS structures designed with different volume fractions are evaluated using quasi-static and dynamic compression tests. The results show that the 3D-CFS structure is a good candidate for shock absorption applications such as personal protective equipment (PPE) applications.