Energy absorption is a key performance criterion for several engineering structures. Lightweight lattice structures are better suited for this purpose. The convolute design patterns that exist in nature are proven effective for several engineering applications. In this paper, a George lily flower leaf is considered to build a novel 3D open lattice pattern for specific energy absorption (SEA) purposes. A multi-cellular specimen is designed and fabricated using Vat photopolymerization 3D printing process. Quasi-static compression tests have been conducted and the performance of proposed structure is compared with 2.5D closed thin-walled structures and found the proposed 3D open lattice structure has shown significant improvement in SEA over other thin-walled structures.

The 2.5-dimensional (2.5D) infill structures are gaining more attention due to their better energy absorption capabilities and lightweight. The additive manufacturing eases the fabrication of these structures and made them accessible for industrial and transport applications. The present work is focused on enhancing energy absorption capability, and mean crush force (MCF) for a novel nature-inspired 2.5D infilled structure through nature-inspired 2.5D geometries. Six nature-inspired geometries are considered for a comparative analysis with the proposed novel snowflake-inspired 2.5D infilled structure to sustain under quasi-static out-plane loading. These structures are cylindrical shells filled with different infill configurations and maintained at constant volume. The structures are fabricated using three-dimensional printing through the digital light processing technique with photopolymer resin and tested under compressive out-plane quasi-static loading conditions. Numerical simulations were performed by ANSYS and compared with experimental results to corroborate the reliability. The effect of infill configurations and supported ribs on the crushing behaviour is discussed in detail. The results reveal a significant improvement in MCF, specific energy absorption, and confined crushing deformation for the proposed lightweight 2.5D infill structures.

Recently, cellular lattice structures are gaining research attention due to their lightweight and high energy absorption. Interpenetrated lattice structure is a combination of two or more regular lattices with the same volume and without any contact at the unit level. The interpenetrated tessellated lattice (I-PTL) structures are better known for load sharing and energy absorption applications. In the current research, regular unit cell lattices such as cubic, beam lattice, body-centered cubic, and octahedron are considered to fabricate penetrated and interpenetrated cellular lattice structures and tested for energy absorption on quasi-static loading. These structures were fabricated using a Vat polymerization three-dimensional printer and tested as per the American Society for Testing and Materials (ASTM) standards, and the results were compared with numerical simulation using ANSYS. The penetrated tessellated lattice structural and I-PTL behavior deliver energy transfer controlled by the surface and solid joint interactions. The enhancement in mechanical properties is observed with the controllable compliance and specific energy absorption of the lattice structure.

Lattice structures exhibit significant potential for superior energy absorption under both static and dynamic loading conditions when compared to solid infill designs. This advantage arises from their distinctive properties, including low relative density, high flexibility, and enhanced compressibility. In this study, a novel type of infill lattice structure, termed the Different Conformal Lattice Structure (DCLS), was developed. DCLS is constructed through the tessellation of Simple Cubic (SC), Body-Centered Cubic (BCC), and Face-Centered Cubic (FCC) lattice configurations. The lattice structures were designed using Fusion360, incorporating optimized infill geometries characterized by both constant and variable relative densities achieved by varying the strut diameters of the individual lattices. Fabrication was performed using the Stereolithography (SLA) process, and the structures were subjected to quasi-static compression testing on a dynamic universal testing machine. Additionally, dynamic characterization was conducted using a Split Hopkinson Pressure Bar (SHPB) apparatus, and the results were compared with finite element simulations. The Experimental findings revealed that specific DCLS configurations, particularly EVT-BFS-2.5, demonstrated exceptional performance, achieving the highest specific energy absorption (SEA) values, exceeding 28 MPa under dynamic loading. This represents an impressive 1866.97% increase compared to quasi-static testing. Finite element analysis corroborated these experimental results, showing excellent agreement and validating the accuracy of the simulations. The study underscores the potential of DCLS with optimized tessellation patterns to significantly enhance energy absorption capabilities. These findings position DCLS as a promising solution for applications demanding lightweight, high-performance energy-dissipative materials.