Mechanical properties of a new 3D printed gradable porous cellular lattice structure considering surface-to-volume capability

In recent years, significant progress in additive manufacturing (AM) techniques has enabled the design and manufacturing of cellular structures with precise micro-architecture and complex cell topologies. This advancement has significantly bolstered the manufacturing of porous materials, leading to the enhancement of their mechanical properties without compromising their lightweight nature. In this paper, a new cellular structure with cell migration capability for the regeneration of bones is designed and introduced. Uniform and functional graded porous lattice structures are manufactured based on the new unit cell with AM technology. The mechanical properties of the unit cell and the cellular structures in two directions are derived analytically. To validate analytical mathematical equations, numerical modeling and experimental tests are conducted. The results of experimental, numerical, and analytical studies are compared to each other and show good agreement. The discrepancy between the yield stress values obtained from the analytical and experimental models of the functional specimen falls within an acceptable range of error regarding usual uncertainties in manufacturing process and surface quality besides the theoretical limitations. Finally, we utilize the genetic algorithm to perform single and multi-objective optimizations on the performance of the unit cell. The optimization results indicate that the new unit cell with optimized lengths sides can improve cell migration and bone regeneration according to the mentioned criteria for the optimization.