基于快速成型技术的复合材料夹芯结构的性能研究

发布时间：2018-10-16 14:05

【摘要】：复合材料夹芯结构具有质量轻、单位质量强度大等优点,其中网格结构芯子能够充分发挥轻质结构的强度与刚度,在航空航天、运输、军事及民事等方面有广泛的应用。本文以增材制造技术(3D打印)代替传统制造工艺,以PLA(聚乳酸)为材料制备不同芯子结构的复合材料夹芯结构,探讨不同芯子结构对复合材料夹芯结构力学性能的影响。具体研究内容:本文首先应用3D打印机制备聚乳酸(PLA)的拉伸及压缩试样,对其进行力学性能测试,获得PLA相应性能参数。结果表明,3D打印的PLA的拉伸强度与注塑成型的Nature WorksTM PLA Polymer 6202D的拉伸强度值非常相近。利用UG画图软件设计并打印出Bi-grid、Tri-grid、Quadri-grid和Kagome-grid四种开孔芯子结构,制备复合材料夹芯结构,研究其在弯曲及侧压载荷作用下的刚度和强度问题,并与Nomex蜂窝结构进行对照,指出这种新型轻质结构的优势。结合有限元分析和三点弯曲测的结果可知,Bi-grid夹芯结构的失效模式为芯子与面板脱粘,而其他三种结构均是由芯子破坏导致结构彻底失效。Quadri-grid夹层结构的力学性能最佳。在Bi-grid、Tri-grid、Quadri-grid和Kagome-grid四种开孔夹芯结构复合材料的基础上,设计了四种闭孔结构。并从模拟分析及实验角度对其弯曲性能进行了分析。结果表明,采用四种闭孔夹芯结构的失效模式与开孔基本相同,Bi-grid闭孔芯子结构的韧性有所增大。闭孔结构相对于开孔结构在质量有所增加的情况下,比强度有了明显的提高。为了有效地使用复合材料,本文设计了三种分级蜂窝芯子夹芯结构,并对其复合材料夹芯结构的弯曲性能、压缩性能及冲击后压缩性能进行了研究。测试结果表明,分级蜂窝结构不适合用在对抗弯、抗剪要求较大的环境中,但增加级数可以实现结构更佳的压缩性能属性。冲.击后压缩测试结果表明,2nd Order Hierarchy夹芯结构表现出了良好的能量吸收功能,具有良好的弹性属性。
[Abstract]:The composite sandwich structure has the advantages of light weight and large unit mass strength, among which the grid structure core can give full play to the strength and stiffness of the lightweight structure. It has been widely used in aerospace, transportation, military and civil affairs and so on. In this paper, the material augmentation technology (3D printing) is used to replace the traditional manufacturing process, and PLA (Polylactic acid) is used as the material to fabricate the sandwich structure of the composites with different core structures, and the effects of different core structures on the mechanical properties of the sandwich structures of the composites are discussed. Research contents: firstly, the tensile and compression specimens of polylactic acid (PLA) were prepared by 3D printer. The mechanical properties of PLA were tested and the corresponding properties of PLA were obtained. The results show that the tensile strength of 3D printed PLA is very close to that of injection molding Nature WorksTM PLA Polymer 6202D. Four kinds of open core structures of Bi-grid,Tri-grid,Quadri-grid and Kagome-grid were designed and printed by UG drawing software. The composite sandwich structures were prepared. The stiffness and strength of the sandwich structures under bending and lateral compression were studied. The results were compared with those of Nomex honeycomb structures. The advantages of this new light structure are pointed out. The results of finite element analysis and three-point bending test show that the failure mode of Bi-grid sandwich structure is core and panel debonding, while the other three kinds of structure are caused by core failure, and the mechanical properties of Quadri-grid sandwich structure are the best. On the basis of Bi-grid,Tri-grid,Quadri-grid and Kagome-grid, four kinds of closed pore structures were designed. The bending properties are analyzed from the point of view of simulation and experiment. The results show that the failure mode of the four closed hole sandwich structures is basically the same as the open hole structure, and the toughness of the Bi-grid closed hole core structure increases. The specific strength of the closed pore structure is obviously improved when the quality of the structure is increased compared with that of the open hole structure. In order to use the composites effectively, three kinds of honeycomb core sandwich structures were designed, and the bending, compression and post-impact compression properties of the sandwich structures were studied. The test results show that the hierarchical honeycomb structure is not suitable for use in the environment where the bending resistance and shear resistance are high, but the better compression properties of the structure can be achieved by increasing the number of stages. Go. The results of post-impact compression test show that the 2nd Order Hierarchy sandwich structure has good energy absorption function and good elastic properties.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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