Mechanical behavior and material modeling of fused filament fabricated PEEK based on TPMS lattices: a comparative study

This study explores the mechanical and morphological properties of architectured lattices, driven by additive manufacturing advancements, and compares different finite element analysis (FEA) methods that are often used to predict the mechanical behavior and failure mechanisms of these lattices. FEA methods based on various material models, including Homogenization (AH), Arruda-Boyce (AB), Yeoh hyperelastic (YH), and Johnson–Cook (JC), are compared to address limitations in classical models, such as the classical rubber elasticity model, the Ogden model, and the polynomial model, with respect to experimental verification under uniaxial compression testing of additively manufactured poly ether ether ketone (PEEK). PEEK lattices with 50% porosity were produced via fused filament fabrication (FFF) utilizing triply periodic minimal surface (TPMS) structures based on two specific unit cell geometries: gyroid and diamond. Our analysis, involving both elastic and yielding regions, revealed the superiority of the JC model in predicting the mechanical properties of gyroid-based lattice structures and the superiority of the AB model for diamond-based lattices. This study highlights the crucial role of material models in the computational analysis of lattice structures’ mechanical behavior. Discrepancies observed between computational and experimental outcomes are attributed to manufacturing defects and constraints in the material models employed.