Design Optimization of Lattice Structures under Compression: Study of Unit Cell Types and Cell Arrangements

Area of Science:

• Additive Manufacturing
• Materials Science
• Mechanical Engineering

Background:

• Additive manufacturing (AM) facilitates novel structural designs, enabling the creation of lattice structures with superior mechanical properties, notably a high strength-to-relative-density ratio.
• Commercialization of lattice structures necessitates defining their geometric designability and characterizing mechanical responses, particularly compressive strength.
• A comprehensive understanding of unit cell topology and its influence on mechanical behavior is crucial for optimizing lattice structure performance.

Purpose of the Study:

• To establish an optimized design process for lattice structures.
• To develop a characterization database for differentiating unit cell topologies.
• To guide unit cell selection for compression-dominated applications.

Main Methods:

• Conducted linear static finite element analysis (FEA) and nonlinear FEA.
• Performed experimental tests on 11 types of unit cell-based lattice structures (20 mm × 20 mm × 20 mm).
• Analyzed correlations between unit cell types, topologies, relative densities, array patterns, and mechanical properties.

Main Results:

• Identified specific lattice structures (simple cubic, octahedron, truncated cube, truncated octahedron) with optimal axial compressive strength at a 3 × 3 × 3 array pattern under consistent relative densities.
• Established correlations among unit cell characteristics, topology, density, array pattern, and mechanical performance.
• Demonstrated the influence of these factors in predicting lattice structure behavior.

Conclusions:

• Optimized design processes and characterization databases are essential for the effective application of lattice structures.
• Certain unit cell topologies exhibit superior compressive strength, providing valuable guidance for material selection in engineering applications.
• The identified correlations offer a predictive framework for the mechanical behavior of lattice structures in compression-dominated scenarios.