Temperature‐Dependent Multiaxial Ratchetting of Polyamide 12 Fabricated by Selective Laser Sintering

ABSTRACT This study investigates the temperature‐dependent multiaxial ratchetting of polyamide 12 fabricated by selective laser sintering, with particular emphasis on the roles of sintering interface and voids. The results demonstrate that both the multiaxial ratchetting strain and the associated irreversible viscoplastic deformation increase with increasing temperature. The polyamide 12 exhibits an additional softening effect under the non‐proportional multiaxial loading, and the magnitude of the additional softening effect depends strongly on the shape of the multiaxial loading path. Additionally, the multiaxial ratchetting exhibits a strong dependence on the building orientation at room temperature, with the ratchetting strain increasing in the order of X 0, X 90, and X 45 orientations (i.e., an increase of approximately 30% from the X 0 to X 45 orientation). However, the effect of building orientation on ratchetting diminishes at elevated temperatures. This is because the polyamide 12 is mainly in a rubbery state at elevated temperatures, where the ratchetting deformation is less affected by void defects. These findings provide guidance for the rational design and reliability evaluation of polyamide 12 components fabricated by selective laser sintering under multiaxial loading across different temperatures.