Exploring the mechanical performance of advanced architectured composites: Computational modeling, 3D printing, and experimental evaluation

Abstract

In this study, the novel triply periodic minimal surfaces (TPMS) are converted into three-dimensional solid sheet networks and used as reinforcements within a matrix creating an interpenetrating phase composites (IPC). Schwarz P (P), Schwarz D (D), Schwarz CLP (CLP), Schoen I-WP (IWP), Nevious C(P) (Nevious), Schoen G (Gyroid), Fischer and Koch S (S) TPMS architectures are investigated, modeled using the finite element method, and their effective elastic properties (Young’s, bulk, and shear Moduli, Poisson’s ratio) are evaluated and compared with traditional composites (particulate and fibers). Each architectured unit cell is then manufactured using 3D printing technology (Connex 260). Where the unit cell is intended to represent the smallest building block of distribution of matter within materials. Next, an extensive experimental evaluation for Young’s modulus, toughness, ductility, and strength is undertaken for all architectures. The deviation of finite element model from experimental data is discussed and complemented by scanning electron microscope (SEM) imaging. Moreover, the degree of the anisotropy of each architectures were investigated by evaluating their corresponding Zener anisotropy ratios. Accordingly, categorized the symmetric architectures to possess cubic symmetry, while asymmetric ones to possess transversely isotropic properties. Besides the geometrical anisotropy, an interesting 3D printing induced anisotropy was observed, and hence reported and discussed. The effects of the architecture, volume fraction of each architecture, and contrast in elastic properties between the two phases in IPC are studied. The special cases of material pairing, where contrast goes to infinity and zero are also studies, where both cases represent foam and porous media, respectively. The TPMS reinforcements show a clear dominance over the effective properties in all cases. Besides the interpenetrating phase composite of Schwarz P (P), Schoen I-WP (IWP), and Koch S (S) demonstrated outstanding multifunctional attributes where mechanical properties where enhanced simultaneously with negligible compromises.

Date of Award	May 2015
Original language	American English
Supervisor	Rashid Abu Al Rub (Supervisor)