Numerical and experimental study of stress-field-driven TPMS hybrid-gradient SLM lattice for impact cushioning

The hybrid TPMS lattice structure is designed to buffer severe impacts and large overloads experienced by high-dynamic systems. This study analyzes the energy absorption requirements of buffering systems in breech pressure launch equipment. We first establish design rules for lattice buffer structures from a systemic perspective and propose a stress field driven hybrid gradient TPMS lattice fusion method. This approach utilizes original impact overload contour maps as lattice data input and implements variable gradient designs across different lattice regions through a porosity gradient strategy. Combining actual working conditions and structural constraints, we conduct parametric modeling alongside static and dynamic simulations to analyze stress distribution, deformation modes, load bearing capacity, and energy absorption characteristics. Lattice buffer units were fabricated using laser powder bed fusion (LPBF) with ultrafine 316L metal powder. Static compression and quasi dynamic simulation methods validated that the field driven lattice design enhances total energy absorption by 19.5% and reduces peak stress on sensitive components to 28.5% of that in unbuffered structures. The maximum error between experimental and simulation results was 14.65%. This research provides valuable insights for impact load protection design in high dynamic equipment.