Effects of loading strain rates on mechanical response and energy dissipation mechanisms of laser powder bed fusion-fabricated porous metallic structures

AlSi10Mg protective structure is prone to unpredictable damage and instability under dynamic impact, and load transmission can cause the failure of key components of the aircraft and threaten mission and return safety. It is urgent to study its impact dynamic response law and the protection mechanism of core deformation and node energy dissipation, including progressive collapse and stress redistribution in the core region, as well as preferential energy dissipation driven by localized plastic deformation and damage at nodes.This study combines the design concept of triply periodic minimal surfaces (TPMS) to optimize the design of three highly representative AlSi10Mg structures with different volume fractions. An improved SHPB experimental technique is constructed to conduct experimental characterization research, and it is pointed out that the macroscopic damage evolution process of the three structures and the macroscopic fracture failure are the products of the synergistic evolution of two microscopic damage mechanisms, micropores and cleavage plane characteristics. Developed high-precision numerical simulation technology, provided the full field stress distribution, strain form, and sensitive areas, and revealed the mechanism of crack propagation and stress release. An intrinsic correlation model between the compressive strength of the AlSi10Mg structure and its loading strain rate has been established, which precisely characterizes the inherent correlation law governing the two parameters. The research results can provide core theoretical basis and common technical support for the reverse design of aerospace protective structures with higher protection levels.