多层泡沫铝夹芯结构准静态力学性能和吸能特性研究

采用闭孔泡沫铝和铝合金板制备单层夹芯板和六种多层夹芯结构。通过分析胞孔变形模式和宏观变形模式,研究了夹层板和芯层数量对结构准静态压缩力学性能和吸能特性的影响机制。结果表明：夹层板通过调节芯层间应力状态使芯层逐层坍塌,减少了由倾斜变形带的形成和延伸所导致的多芯层同步变形、横向滑动以及两侧滑移,使结构具有更高的坍塌应力、平台应力、单位体积吸能量以及更小的致密应变；芯层数量的增加导致无夹层板结构中变形带的长度和数量增加,从而改变了其宏观变形模式,致使结构两侧滑移现象加剧,同时积累了有夹层板结构中多个芯层中的胞孔缺陷,因此影响了逐层稳定变形,导致致密应变增大,坍塌应力、平台应力和单位体积吸能量减小,致密应变处的吸能效率降低。与其他结构相比,三层泡沫铝夹层板具有最佳的抗压强度和吸能性能。

Study on the quasi-static compression mechanical properties and energy absorption characteristics of multilayer aluminum foam sandwich structure

Single-layer sandwich panels and six kinds of multilayer sandwich structures were prepared using closed-cell aluminum foam and aluminum alloy sheets. The cellular and macroscopic deformation modes were analyzed to study the influence mechanism of the plates and layer number on the quasi-static mechanical properties and energy absorption characteristics. The results show that the plates can adjust the stress state and make the cores collapse layer by layer, which reduces the multilayer synchronous deformation, lateral and bilateral slip caused by the formation and extension of the inclined deformation bands, so that the structure has higher collapse stress, platform stress, energy absorption per unit volume and smaller densification strain. The increase of the layer number leads to the increase of the length and number of the deformation bands in the structures without plate, thus changes the macroscopic deformation mode, results in the aggravation of the slip phenomenon on both sides, leads to the accumulation of cellular defects in the structures with plate, affects the stable deformation, results in the increase of densification strain, the reduction of collapse stress, platform stress and energy absorption per unit volume, and the decrease of energy absorption efficiency at densification strain. Compared with other structures, the three-layer structure with plates has the best compression resistance and energy absorption properties.