铝蜂窝材料动态压缩力学性能及吸能分析

A Study on Dynamic Compressive Mechanical Behaviors of Aluminum Honeycombs

采用分离式霍普金森压杆(SHPB)技术,研究了边长为1.0~1.83 mm,箔厚度为0.04~0.06 mm,相对密度为0.05~0.06的三种5052 H18铝合金蜂窝的动态压缩行为。结果表明:铝合金蜂窝在高应变率条件下动态压缩与其准静态压缩的应力–应变曲线均具有明显的多孔材料三阶段特征,其塑性屈服平台的应变量大于65%,单位体积吸能为3.32~5.03 MJ/m3,最大吸能效率为0.65~0.7。虽然只有边长为最小的(1 mm)铝蜂窝的失稳屈服极限应力明显高于稳态屈服平台应力,但三种铝蜂窝的稳态屈服平台应力均具有明显的应变率敏感特性,边长/箔厚相同的两种铝蜂窝(1.0 mm/0.04 mm, 1.5 mm/0.06 mm)的体积吸能与吸能效率差别不大。

Split Hopkinson Pressure Bar (SHPB) method was employed to determine the compressive dynamic mechanical properties of three kinds of honeycombs, which were made of Al alloy 5052H18 with side lengths (b) of 1.0 - 1.83 mm, foil thicknesses (t) of 0.04 - 0.06 mm and relative densities (ρ) of 0.05 - 0.06. Results indicated that: at high strain rate, the dynamic stress-strain curves of the Al honeycombs show a general "three-stage"characteristic of porous materials. The densification strains are greater than 65%. The specific range of energy absorption is 3.32 - 5.03 MJ/m3, and the range of the maximum values of energy absorption efficiency is 0.65 - 0.7. Even though only the yield stress of the Al honeycomb with the shortest side length (1 mm) is greater than itself plateau stress, all the tested Al honeycombs have the character of strain rate sensitivity. The specific energy absorption and the energy absorption efficiency have no significant difference between the two Al honeycombs with the same ratio of side lengths/foil thickness (1.0 mm/0.04 mm, 1.5 mm/0.06 mm).