基于晶界强化的多晶体点阵超材料设计与耐撞性研究  

Study on Design and Crashworthiness of Polycrystal Lattice Metamaterials Based on Grain Boundary Strengthening

作　　者：罗耿 肖尧之 薛凯峰 陈轶嵩 Luo Geng;Xiao Yaozhi;Xue Kaifeng;Chen Yisong(School of Automobile,Chang’an University,Xi’an 710016)

机构地区：[1]长安大学汽车学院,西安710016

出　　处：《汽车工程》2024年第12期2209-2219,共11页Automotive Engineering

基　　金：国家重点研发计划子课题(2021YFB2501202);国家自然科学基金(52302427);长安大学中央高校基金(300102223101)资助。

摘　　要：点阵结构力学超材料由于其良好的力学特性及耐撞性,广泛地应用于各类防护结构。传统点阵材料多为周期性排布的规则多孔材料,受金属材料微观晶体结构启发,本文在点阵材料的设计中引入了随机的晶界结构,提出并采用3D打印技术制备了多晶体点阵材料试件,进一步地,基于经试验验证的有限元模型开展了其耐撞性研究。研究结果表明:与单晶体点阵材料相比,当晶格角度相同时,多晶体点阵材料的比吸能提升较大,尤其在30°角度下提升了143%;多晶体点阵材料的晶粒尺寸、晶粒内晶格角度、晶粒随机度均会影响其耐撞性,当晶粒变小时,材料的吸能过程会更加平稳,但由于边界效应的影响,晶粒过小反而会加剧吸能过程中的波动;45°晶格角度与30°/60°随机晶格角度排列下的多晶体点阵材料有着平稳的吸能过程;随机度较大的多晶体点阵材料其能量吸收过程更加平稳。本文提出的新型多晶体点阵力学超材料可以有效地提高传统点阵材料的耐撞性,可为发展新型轻质点阵超材料的设计与优化提供指导。Lattice mechanical metamaterials are widely applied in various protective structures due to their excellent mechanical properties and crashworthiness.Traditional lattice structures are often composed of periodically arranged regular porous materials.Inspired by the microcrystalline structures of metals,in this paper random grain boundary structures are incorporated into the design of lattice materials,then polycrystal lattice material specimens using 3D printing technology are prepared.Furthermore,crashworthiness studies are conducted based on the finite element models validated by experiments.The results show that compared to single crystal lattice materials,polycrystal lattice materials significantly improve specific energy absorption(SEA)at the same lattice angle,especially with 143%increase at the lattice angle of 30°.The crashworthiness of polycrystal lattice materials is influenced by grain size,intragranular lattice angle,and grain randomness.When grain size decreases,the energy absorption process becomes smoother,but excessively small grains may exacerbate fluctuations in the energy absorption process due to boundary effect.Polycrystal lattice materials with a 45°lattice angle and random lattice angles of 30°/60°exhibit stable energy absorption processes,and those with higher randomness in grain orientations show an even smoother energy absorption process.The novel polycrystal lattice mechanical metamaterials proposed in this paper can effectively enhance the crashworthiness of traditional lattice materials and provide guidance for the design and optimization of new lightweight lattice metamaterials.

关 键 词：点阵结构 力学超材料 晶界强化 变形模式 能量吸收 

分 类 号：U465[一般工业技术—材料科学与工程]