泡沫铝夹心结构不同温度及疲劳荷载下的力学性能与结构优化实验研究

As specific material properties, Aluminium Foam Sandwich(AFS) panels have a wide range of potential applications such as aerospace, military and engineering applications, due to its excellent energy dissipation, high impact strength, higher working temperature and thermal insulation. However, the existing research work on AFS panels has not enough for better describing the relation between its mechanical behaviors and its structure. In the proposed project, the techniques, such as thermal imaging and digital image processing will be employed to investigate the deformation responses, energy absorption, failure modes and damage involution of AFS panels under different temperature field and dynamical loading. The correlation of the mechanical properties of AFS panels with their physical and geometric properties will be studied. By using of analytical solution and numerical simulation, it will characterize the impact loading and energy absorption of AFS with its structural response under different temperature field and loading. The goal of the proposed research is to investigate and design AFS panels with high specific stiffness and strength, excellent plastic energy absorbing capabilities, and it will be achieved by optimizing different parameters, such as materials of core and face sheets or design geometry of panel with the knowledge of operating failure mechanism at the design loads. It will suit various requirements with minimal weights, desired stiffness and strength, such as for application on the design of lighter spacecraft, high speed marine craft and railway wagons. It can also make a great contribution on the development of experimental mechanics by extending its area of application.

泡沫铝夹心结构除具备优异功能材料特性外，还具有很高的能量耗散力，抗冲击强度和耐热能力等，在航空航天、军事和民用等领域具有广泛的应用前景。然而，目前实验和理论方面对其结构与力学性能的研究与评价还不完善。本项目拟采用包括红外成像及图像处理技术等手段观测多孔铝夹心结构不同温度，疲劳荷载下变形行为特征，能量吸收及结构失效过程与破坏模式，研究其细观非均匀性及材料几何/物理参数的变化与宏观力学性能之间的关系；结合理论分析与数值模拟建立不同温度下泡沫铝夹心结构的承载、吸能与结构构型和参数间的关系，以具有优异刚度、强度和良好抗冲击吸能性能为研究目标，对结构的几何参数、力学性能参数进行优化设计，为泡沫铝夹心结构的多学科优化设计以及抗冲击防护评估等方面提供技术支持，满足空天飞行器、高速轨道车辆、舰船等对超轻材料与结构的需求。本项目的研究还能促进实验力学等相关基础学科的研究与发展，具有重要的理论与实际意义。

泡沫铝夹心结构除具备优异功能材料特性外，还具有很高的能量耗散力，抗冲击强度和耐热能力等，在航空航天、军事和民用等领域具有广泛的应用前景。本项目主要针对泡沫铝夹心结构在静、动荷载与不同温度条件下的力学行为开展实验研究和理论分析。主要研究内容包括：一、闭孔泡沫铝压缩力学性能、泡沫铝三明治梁在准静态三点弯曲荷载作用下的变形失效模式以及芯材厚度、加载跨距、孔隙结构对其弯曲性能的影响；二、对优化设计的泡沫铝夹芯梁结构完成了三点弯曲往复荷载试验，分析获得结构尺寸对其往复弯曲荷载性能的影响规律，以及结构破坏模式的影响形式和刚度退化的机制；三、实验研究了温度变化(-80摄氏度, -40摄氏度, 室温，150摄氏度及300摄氏度)对闭孔泡沫铝压缩力学特性、泡沫铝三明治梁静态三点弯曲荷载作用下变形行为的影响；四、利用激光干涉测量技术研究了闭孔泡沫铝的非线性振动特性。通过本项目的研究取得以下的成果：一、加载跨距、孔隙结构一定时，芯材越厚，极限承载能力越大，面板屈服断裂的可能性减小，压头压入的可能性增大；当芯材厚度、孔隙结构一定时，跨距越大，极限承载能力越小，面板屈服断裂的可能性越大，压头压入式的可能性越小；当跨距、芯材厚度一定时，类球形泡沫铝三明治梁的承载能力比多面形泡沫铝三明治梁高；二、获得结构尺寸对往复三点弯曲荷载下力学性能的影响规律，以及结构破坏模式的影响形式和刚度退化的机制，结果表明：结构循环寿命随着厚跨比的增加而逐渐减小；三、泡沫铝的压缩屈服应力，泡沫铝三明治结构三点弯曲承载极限受温度影响较大，温度越高极限承载能力越弱；四、首次通过实验发现闭孔泡沫铝具有明显的三次非线性振动特性。以上研究成果对于设计具有优异刚度、强度和良好抗冲击吸能性能泡沫铝夹心结构；以及为优化结构几何参数、静动态力学性能参数，为多学科优化设计以及抗冲击防护，振动特性评估等方面提供实验数据支持。