PSI - Issue 68

A. Ceci et al. / Procedia Structural Integrity 68 (2025) 372–378

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A. Ceci et al. / Structural Integrity Procedia 00 (2025) 000–000

1. Introduction Lattice structures are innovative designs composed of repeated unit cells (Tao, W. et al. (2016)), offering significant advantages in various engineering applications where weight reduction, energy, and sound absorption or a combination of them are required, optimizing material utilization. Lattice structures require careful design of the unit cells to meet specific engineering requirements, balancing complexity and manufacturability. Advanced CAD approaches are essential for managing the multiscale modeling of these structures (Ahmad, A. et al. (2023)). In medical implants, porous lattices mitigate stress shielding, improving osseointegration and reducing the risk of complications (Abdullah, N.N.A.A. et al. (2024)). The maritime industry benefits from the integration of lattice structures in ship hulls, improving structural properties and optimizing material usage (Armanfar, A. et al. (2024)). The rise of AM has revolutionized the production of lattice structures, enabling complex designs that traditional methods cannot achieve (Ahmad, A. et al. (2023), Sajjad, U. et al. (2022)). Various materials, including polymers and metals, are employed in the fabrication of lattice structures, each offering unique mechanical properties (Sajjad, U. et al. (2022), Iandiorio, C. et al. (2024)). Despite the numerous advantages offered by lattice structures, significant challenges persist in their design and fabrication, particularly concerning the requirement for advanced techniques and materials to fully realize their potential. This study investigates the fabrication and subsequent mechanical characterization of metallic lattice structures through compression testing, Finite Element Analysis (FEA), and Digital Image Correlation (DIC). 2. Experimental processes Figure 1 shows the various steps of the production process for the structures, using the Lost PLA method.

Metal Structure

PLA model

Plaster Mold

Model preparation

CAD model

Gravity casting

Plaster casting on the PLA model

Slicing

Quenching

3D printing

Burnout

Cleaning

Fig. 1 : Scheme of the Lost-PLA process.

From a structural design perspective, a lattice structure can be generated by repeating a unit cell following a specific 3D spatial pattern. Therefore, the design of a lattice structure includes the design of unit cells, the smallest element that composes and characterizes the entire lattice structure. One of the numerous CAD design methods for 3D lattice structures is parametric modeling, which allows the geometry of the structure to be defined through variable parameters, such as cell size, beam thickness, and density. These parameters can be adjusted to optimize the mechanical or structural properties of the structure. This technique is used to generate lattice structures with repetitive and easily modifiable geometric features. In this work, the unit cell was generated based on a parametric implicit equation: