Influence of Porosity on the Mechanical Behavior during Uniaxial Compressive Testing on Voronoi-Based Open-Cell Aluminium Foam

Abstract

We have studied an application of the Voronoi tessellation method in the modeling of open-cell aluminium foam under uniaxial compressive loading. The Voronoi code was merged with computer-aided design (CAD) for converting the polyhedral model into an irregular open-cell cellular structure to create porous samples for compression testing simulations. Numerical simulations of the uniaxial compression uniformly over the upper surface of the sample in the z-axis direction at a constant 20 N load was realised. Samples with three different porosities (30%, 60% and 80%) were studied. A nonlinear elasto-plastic material model with perfect plasticity, without hardening, based on the von Mises yield criterion was applied below 10% strain. Corresponding stress–strain curves were observed and the influence of porosity on deformation mechanism was discussed. Samples with higher porosity exhibited significantly higher normal stress under the same load, and increased stress plateaus. An increase of porosity produced an increase of both compressive and tensile stresses and struts exhibited complex stress fields. Voronoi-based modeling was in accordance with experimental results in the literature in the case of the quasi-static condition and linear elastic region (below 1% strain). Further study is necessary to enable the simulation of real dynamic behaviour under all deformation regimes by using the Voronoi tessellation method.

Creation and finite-element analysis of multi-lattice structure design in hip stem implant to reduce the stress-shielding effect

“…Similarly, von Mises stress was used in the evaluation of porous materials in many studies in the literature. 41,53–59 Moreover, the von Mises stresses on the implanted hip stem are an important indication in assessing the transfer of load from the hip implant stem to the femoral bone. 38 However, it may be misleading to use only the maximum von Mises values when evaluating this load transfer phenomenon, especially in hip implant stem having lattice designs.…”

Porous Scaffold Design for Additive Manufacturing in Orthopedics: A Review

“…In their study, the critical load of the Voronoi designed porous structures was increased by nearly 300%, which showed the ability for internal load-bearing implant structure. For another model built with algorithm, the results also showed that the manufactured model exhibited a high load to weight ratio, which is a crucial parameter for the scaffold (shown in Figure 2D) (Sharma et al, 2019). Voronoi designed scaffold with gradient porosity (60% to 95%) also showed excellent mechanical properties.…”

Influence of foaming agents on mechanical and microstructure characterization of AA6061 metal foams

“…As the porosity increases, the contact surface area decreases which causes sudden increase in stresses as a result of reduced foam strength. 48 Highest tensile strength was observed for wax powder foaming agent whose value equal to 6.16 MPa at a deformation rate of 4.4, followed by magnesium hydroxide of 5.32 MPa at a deformation rate of 4, and TiH 2 equal to 4.3 MPa and deformation of 3.5, respectively (refer Figure 7 and Table 2). Reduced strengths observed with magnesium hydroxide and titanium hydride are attributed to higher porosity in foam samples.…”