Research on the energy absorption performance of diamond structures with axial and transverse porosity gradients under different load-bearing angles

Background In biomedical, aerospace, automotive and marine engineering, there is an increasing demand for high energy absorption behaviour in structures. Triply periodic minimal surface (TPMS) structures, such as Diamond lattices, have emerged as promising solutions due to their light weight nature and excellent energy absorption performance, and thus they have attracted significant research interest. Methods This study explores the energy absorption characteristics and deformation behavior of Diamond structures with varying porosity distributions under different loading angles. Uniform and gradient Diamond structures with axial and transverse porosity distributions were generated. Quasi-static compression tests were performed on the uniform structures, while FE simulations were used to investigate the mechanical and energy-absorption responses of the uniform and gradient configurations. Quasi-static compression tests and finite element (FE) simulations were used to analyze the changes in energy absorption characteristics and deformation/damage modes during the compression process. Results The results show that loading orientation and porosity-gradient direction strongly influence the energy-absorption response of Diamond structures. For the uniform structure, the SEA increased to approximately 8 kJ/kg at a loading angle of 30°, representing an increase of about 33% compared with the 0° and 15° configurations, while the corresponding plateau stress reached approximately 105 MPa. When the loading angle increased to 45°, the SEA decreased to approximately 4 kJ/kg because of earlier densification. Axial-gradient structures exhibited increased plateau stress and slightly enhanced SEA, but their maximum energy-absorption efficiency remained below approximately 35%, compared with about 40% for the uniform structures. Transverse-gradient structures showed plateau stresses comparable to those of the uniform structure with the corresponding average porosity, but tended to densify earlier, resulting in reduced SEA. Conclusion These findings provide valuable insights into the design and optimization of Diamond structures for improved energy-absorption performance under different loading conditions and offer mechanical design guidance that may be relevant to the future development of TPMS structures for biomedical applications.