Mechanical Properties of Architected Polymer Lattice Materials: A Comparative Study of Additive Manufacturing and CAD Using FEM and µ‐CT

Mechanical properties of porous lattice materials can be tuned by the structure. Thus, the effect of the unit cell design on the mechanical properties is of special interest. However, studies often lack an in‐depth investigation of the underlying mechanisms. Additionally, inhomogeneous bulk material properties and structural deviations introduced during manufacturing are often neglected. Here, the impact of the pore shape on Young's modulus, initial peak stress, and energy absorbance of lattice materials is investigated. Structural deviations of 3D‐printed lattice materials from the computer‐aided design (CAD) are examined, and analyze how they affect the mechanical properties. For comparability, the porosity, overall dimensions, and unit cell size of the lattice material are kept constant. Flexible lattice materials assembled of 3 × 3 × 3 unit cells are 3D‐printed (stereolithography). Mechanical properties are determined through uniaxial compression tests and finite element modeling (FEM). Deviations between CAD and 3D‐printed lattice materials are analyzed using micro‐computed tomography (µ‐CT). Combining µ‐CT with FEM revealed the impact of these deviations on the mechanical properties. It is found that the mechanical properties depend indeed on the pore shape. Furthermore, a pyramidal shape along the printing direction and displaced or deformed pores are observed in the 3D‐printed lattice materials, all of which result in reduced mechanical properties.