Stress Concentration and Mechanical Strength of Cubic Lattice Architectures

Abstract

The continuous design of cubic lattice architecture materials provides a wide range of mechanical properties. It makes possible to control the stress magnitude and the local maxima in the structure. This study reveals some architectures specifically designed to reach a good compromise between mass reduction and mechanical strength. Decreased local stress concentration prevents the early occurrence of localized plasticity or damage, and promotes the fatigue resistance. The high performance of cubic architectures is reported extensively, and structures with the best damage resistance are identified. The fatigue resistance and S–N curves (stress magnitude versus lifetime curves) can be estimated successfully, based on the investigation of the stress concentration. The output data are represented in two-dimensional (2D) color maps to help mechanical engineers in selecting the suitable architecture with the desired stress concentration factor, and eventually with the correct fatigue lifetime.

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

“…11) also shows significant engagement from adjacent cells demonstrating the limited influence of stress concentration. Similar observations were made by Lohmuller et al [212] when studying the mechanical strength of cubic lattice architecture.…”

“…The effect of such stress concentrations on the performance of cellular materials is usually quantified using the stress concentration factor ( ) [211][212][213].…”

Numerical investigation of the effective mechanical properties and local stress distributions of TPMS-based and strut-based lattices for biomedical applications

“…Additionally, the relative density or the volume fraction of the lattices plays an important role in the control of their effective properties (Al-Ketan et al, 2020). However, stress concentrations may be observed in various areas of the lattice structures, due to the nature of their topology (Lohmuller et al, 2018). Hence, it is also essential to minimize the stress concentration on the lattices to improve mechanical performances such as fatigue response.…”

“…There are two distinct lattice topology families, the strut-based and the surface-based topologies (Al-Ketan et al, 2018). The first family includes periodic topologies based on cylindrical beams/struts, for instance, octet-truss (Deshpande et al, 2001), BCC (Maskery et al, 2017), the cubic Bravais lattices, and some more complex combinations of the beams (Favre et al, 2018;Lohmuller et al, 2018). The second family includes topologies based on the Triply Periodic Minimal Surfaces (TPMS) concept whose lattices exhibit smoother connections.…”

Generalized tessellations of superellipitcal voids in low porosity architected materials for stress mitigation

“…Specific to cellular architectures, stress concentration has also been studied, but so far to a less degree. Most focused on high porosity metamaterials, hence investigating the relation between stress concentration and geometric imperfections induced by additive manufacturing [51,52]. On the low-porosity front, on the other hand, stress concentration, along with other aspects, such as crack nucleation, has been studied mainly in orthogonally tessellated metamaterials [43,53,54].…”