Spherical porous structures for axial compression

Porous structures have attracted much attention because of the advantages of lightweight and strong energy absorption efficiency. This work proposes a spherical porous structure (SPS) and a square porous structure (SQPS), and the SPS sample is manufactured by selective laser sintering (SLS) technique with the material nylon 11. Their axial compression results of experiment and simulation show that the compressive strength of hollow cylinders is greater than that of porous spheres, and porous spheres are always crushed during compression. SPS exhibits the rapid collapse characteristics of porous spheres layer by layer, and it shows four sharp valley forces and significant negative stiffness characteristic. In addition, the specific energy absorption (SEA) value of SPS is higher than that of SQPS 30.84%. The compression capacity of porous spheres is stronger than that of porous cubes. This study furtherly discuss the mechanical behavior of SPS with different structural parameters. The negative stiffness characteristic, energy absorption efficiency and deformation mode of SPS depends on the strength combination of porous spheres and hollow cylinders, and smaller overall cell size, more cell layers, and thicker cells contribute to improving the anti-compression properties of SPS. The SEA values of SPS- T1.6 and SPS- F7 are 12.52% and 12.16% higher than that of SPS. In summary, SPS shows novel mechanical properties, providing a reference for the design of new energy absorbers.