轻质复合材料波纹夹芯承压立柱的轴向低速撞击响应与吸能机理研究

The optimally designed sandwich column shows excellent load-bearing capacity under axial quasi-static compression, which is a lightweight pressure-bearing structure with important application prospect. However, little work has been published on axial impact of sandwich column, so it is hard to conduct its crashworthiness evaluation and structural design. In this project, the dynamic response and energy absorption mechanism of composite corrugated sandwich column under axial low-velocity impact are studied by experiments, numerical simulations and theoretical analysis. The deformation and failure modes of composite corrugated sandwich column under axial low-velocity impact are obtained by experiments. Finite element models are established to carry out numerical simulations. Based on the existing quasi-static theory, a theoretical model is developed to analyze the failure of composite corrugated sandwich column under axial low-velocity impact. Then the mechanisms of deformation, failure and energy absorption of composite corrugated sandwich pressure-bearing column under axial low-velocity impact are revealed. Several effects, including geometries, material properties, interfacial bonding strength between face-sheet and core, and impact load, on the mechanisms are also investigated. The results of this project can improve the understanding of the axial impact behavior of sandwich pressure-bearing column and provide a theoretical basis for the crashworthiness evaluation and structural design.

经过合理设计的夹芯柱在轴向准静态压缩下表现出优异的承载能力，是具有重要应用前景的轻质承压结构，但目前关于夹芯柱轴向冲击的研究还非常有限，尚无法对其进行耐撞性评价与设计。本项目拟选取复合材料波纹夹芯承压立柱作为具体对象，采用实验、数值模拟和理论分析三种手段对其在轴向低速撞击下的动力响应与吸能机理开展研究。通过实验获得复合材料波纹夹芯柱在轴向低速撞击下的变形与失效模式，建立有限元模型开展数值模拟，基于已有的准静态理论建立复合材料波纹夹芯柱轴向低速撞击失效的理论分析模型，进而揭示复合材料波纹夹芯承压立柱在轴向低速撞击下的变形失效机制与吸能机理，并探究几何尺寸、材料性能、面板/芯材界面粘接强度、冲击载荷强度等因素对变形失效机制与吸能机理的影响规律。本项目的研究可以增进对于夹芯承压立柱轴向冲击行为的认识，为结构耐撞性评价和设计提供理论基础。

经过合理设计的轻质多孔夹芯承压立柱在轴向准静态压缩下表现出优异的承载能力，是具有重要应用前景的轻质承压结构，但目前关于夹芯承压立柱轴向冲击的研究还非常有限，尚无法对其进行耐撞性评价与设计。本项目针对受轴向大质量低速撞击的轻质多孔夹芯承压立柱建立了有限元仿真模型，模拟了实验中夹芯承压立柱在整体屈曲之后出现的两类变形模式，即“芯材剪切-卷曲”与“局部凹陷-塑性铰”，数值结果与实验结果吻合较好；对比了“芯材剪切-卷曲”与“局部凹陷-塑性铰”两类模式下夹芯承压立柱的耐撞性，前者在缓冲性能、能量耗散和变形空间三方面均表现更优；发现了在夹芯承压立柱轴向低速撞击实验中未出现的一类变形模式，即“芯材剪切-不卷曲”，并发现芯材的作用除了耗散能量，还有诱导卷曲的发生；建立了反应夹芯承压立柱几何参数影响的变形机制图，且考虑了面板非对称性的影响，并发现面板与芯材厚度之比过小或过大均不利于结构发挥出更优的耐撞性。通过本项目的研究，揭示了夹芯承压立柱的变形机制与吸能机理，给出了夹芯承压立柱耐撞性的评价方法，从而增进了对于轻质多孔夹芯承压立柱轴向冲击行为的认识，为结构耐撞性设计提供了基础。.在完成相关研究的同时还完成了新型复合材料层合板低速撞击实验、以纤维金属层合板为面板的金属泡沫夹芯梁和以金属泡沫填充sin型波纹为多孔芯材的夹芯梁的大挠度塑性理论、多孔夹芯管横向压缩实验等方面的研究，研究结果将为轻质防护结构设计与应用提供理论和技术支持。