Design of Hierarchical Architected Lattices for Enhanced Energy Absorption

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Hierarchical lattices, composed of architected metamaterials across multiple length scales, offer tunable properties superior to conventional lattices.
• These structures present opportunities for advanced material property manipulation and optimization.

Purpose of the Study:

• To investigate the energy absorption capabilities of 3D hierarchical lattices using finite element analysis.
• To explore the impact of hierarchical order, relative density, and geometric variations on energy absorption performance.

Main Methods:

• Finite element analysis (FEA) was employed to simulate energy absorption under low strain rates.
• Fused Deposition Modeling (FDM) 3D printing was used to characterize the mechanical properties of Thermoplastic Polyurethane (TPU) 85A.
• Simulations compared first- and second-order octet lattices, varying hierarchical order and relative density.

Main Results:

• Introducing hierarchy to octet lattices enhanced energy absorption by four to five times.
• Second-order octet lattices showed a 20% increase in energy absorption with a 45-degree cell orientation change.
• Analytical solutions for effective elasticity modulus validated FEA simulations.

Conclusions:

• Hierarchical lattice design is a promising strategy for significantly improving energy absorption.
• Findings provide a foundation for optimizing lattice structures in energy absorption applications.
• Further research can leverage these insights for novel energy absorption material design.