往复荷载作用下泡沫铝夹芯梁结构的力学行为研究

发布时间：2018-01-30 10:11

本文关键词： 泡沫铝夹芯梁弯曲疲劳厚跨比疲劳寿命刚度退化　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：泡沫铝材料具有良好的力学、电磁学、和声学性能,广泛应用于航空航天、建筑结构、船舶技术、汽车工程等领域。单纯的泡沫铝无法作为工程结构构件,通常与传统的致密金属组成的复合夹芯结构实现了其最佳的力学特性,并且泡沫铝夹芯结构的可设计性强。目前,对泡沫铝及其夹芯结构的力学性能研究主要集中在静态力学性能以及冲击力学性能,而对其疲劳性能的研究非常匮乏。在工程实践中,工程结构经常面临着循环荷载作用,因此,深入研究泡沫铝夹芯结构在往复荷载作用下的力学行为就变得十分迫切。本文以实验研究为主,结合理论分析研究了闭孔泡沫铝夹芯梁结构在循环弯曲荷载下的力学行为。主要的研究内容及成果如下：(一)实验研究了泡沫铝夹芯梁结构在三点弯曲条件下的准静态力学性能,分析了不同厚跨比对泡沫铝夹芯梁结构的极限承载能力、吸能特性、承载能力稳定性的影响,总结出试样破坏模式的发展规律；综合考虑承载、吸能性能,给出了此种结构较合理设计的方法。(二)结合现有纯拉压试验设备,设计并加工了能更好实现三点弯曲模式的疲劳试验夹具。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。结果表明：结构循环寿命随着厚跨比的增加而逐渐减小。(三)完成钢面板的泡沫铝夹芯结构往复三点弯曲试验,结果显示：与铝面板的泡沫铝夹芯结构相比,钢面板的循环寿命有一定程度的提高,但后者的结构破坏模式规律性较不明显。
[Abstract]:Aluminum foam materials have good mechanical, electromagnetic, and acoustic properties, and are widely used in aerospace, building structures, ship technology, automotive engineering and other fields. Pure aluminum foam can not be used as engineering structural components. The composite sandwich structure usually composed with traditional dense metal achieves the best mechanical properties, and the foam aluminum sandwich structure has strong designability at present. The mechanical properties of aluminum foam and its sandwich structures are mainly focused on static mechanical properties and impact mechanical properties, but the fatigue properties of aluminum foam and its sandwich structures are very scarce. Engineering structures often face cyclic loading, so it is urgent to study the mechanical behavior of aluminum foam sandwich structures under reciprocating loads. Combined with theoretical analysis, the mechanical behavior of closed cell aluminum sandwich beam structure under cyclic bending load is studied. The main contents and results are as follows: (1). The quasi-static mechanical properties of aluminum foam sandwich beam structure under three point bending conditions were studied experimentally. The effects of different thickness / span ratios on the ultimate bearing capacity, energy absorption characteristics and stability of the aluminum sandwich beam structure are analyzed, and the development rule of the failure mode of the specimen is summarized. Considering the bearing capacity and energy absorption performance, the reasonable design method of this kind of structure is given. (2) combined with the existing pure tension and compression test equipment. The fatigue test fixture which can better realize the three-point bending mode is designed and machined, and the three-point bending reciprocating load test is completed for the optimized design of aluminum sandwich beam structure. The influence of structure size on the behavior of reciprocating bending load is analyzed. The results show that the cyclic life of the structure decreases with the increase of the ratio of thickness to span. (3). The three-point bending test of aluminum foam sandwich structure is completed. The results show that the cyclic life of steel panel is improved to some extent compared with the aluminum foam sandwich structure, but the failure mode of the latter is not obvious.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.4

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