Design and Mechanical Characterization of Lightweight Lattice Structures Fabricated through Additive Manufacturing

The increasing demand for lightweight, mechanically efficient structures in aerospace, automotive, biomedical, energy, and transportation engineering has accelerated the development of architected cellular materials fabricated through additive manufacturing. Lattice structures provide a particularly attractive solution because material can be distributed according to structural requirements while maintaining low mass, controllable stiffness, and enhanced energy-absorption capability. This paper presents a comprehensive mechanics-based investigation of the design and mechanical characterization of lightweight lattice structures fabricated using additive manufacturing. Three representative architectures, body-centred cubic (BCC), octet-truss, and gyroid triply periodic minimal surface (TPMS), are considered at relative densities of 0.15, 0.25, and 0.35. The study examines relative-density scaling, deformation mechanisms, strut slenderness, buckling resistance, elastic modulus, compressive strength, plateau behaviour, specific structural properties, and energy absorption. Word-compatible analytical equations are incorporated to establish relationships between lattice geometry and structural performance. A systematic methodology is also proposed for laser powder bed fusion fabrication, quasi-static compression testing, geometric characterization, and finite element validation. Analytical scaling demonstrates that stretching-dominated lattices can maintain comparatively high specific stiffness at low density, while bending-dominated lattices experience a stronger stiffness reduction as material is removed. Increasing relative density from 0.15 to 0.35 theoretically increases a linearly density-dependent property by approximately 2.33 times, while a quadratic stiffness relationship produces an increase of approximately 5.44 times. The study further establishes that unit-cell size, strut slenderness, surface irregularity, dimensional deviation, build orientation, internal defects, and node geometry significantly influence the difference between ideal and as-built mechanical behaviour. The proposed framework provides a technically rigorous basis for developing next-generation lightweight load-bearing structures, energy absorbers, aerospace components, and mechanically optimized additive-manufactured systems.