新型起圈织物增强蜂窝夹层板力学性能研究
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摘要
复合材料夹层结构由于其优越的力学性能被广泛应用于当今航空工业,但是传统编织二维复合材料夹层板在厚度方向抗分层与抗剥离能力较差,起圈织物作为一种新型三维机织复合材料,可通过z方向预织的毛圈有效改善复合材料夹层板在厚度方向的力学性能。但目前国内对起圈织物增强夹层结构的力学性能研究较少。对起圈织物蜂窝夹层板的平拉力学性能进行研究,通过真空袋成型工艺制作了玻璃纤维起圈织物增强夹层板与传统玻璃纤维夹层板并完成平拉试验,获得了平拉载荷作用下的力-位移曲线与拉伸强度。试验结果表明起圈织物增强蜂窝夹层板具有更高的平拉模量与平拉强度。主要原因是固化时,起圈织物夹层板的蜂窝夹层中形成了环氧树脂胶柱体。胶柱体参与了芯材受力,增大了拉伸模量,同时嵌入胶柱体的毛圈也提高了起圈织物夹层板的平拉强度。由此可以得出结论:起圈织物可以有效提高蜂窝夹层板的平拉性能。最后就研究中出现的一些问题提出相应的改进方法与思路。
The composite sandwich structure is widely used in today's aviation industry because of its superior mechanical properties,but the traditional woven two-dimensional composite sandwich plate has poor resistance to delamination and peeling resistance in the thickness direction. As a new type of three-dimensional woven composite material,the looping fabric( U-cor) can effectively improve the mechanical properties of the composite sandwich structure in the thickness direction by pre-woven fabric loops. However,at present,there are few studies on the mechanical properties of the looped fabric reinforced sandwich structure in China. In this paper,the mechanical properties of flat-pulled honeycomb sandwich panels are studied. Firstly,a glass fiber looped fabric reinforced sandwich panel and a traditional glass fiber sandwich panel were fabricated by the vacuum bag forming process,and the flat pull test was completed. The force displacement curve and tensile strength were obtained. The test results show that the looped fabric reinforced honeycomb sandwich panel has a higher flat modulus and flat tensile strength. The main reason is that epoxy resin formed glue columns in the looped fabric panel during curing. The glue columns are involved in the stress of the core material to increase the tensile modulus,and the loops embedded in the glue columns also improves the flat tensile strength. It can be concluded that the loop fabric can effectively improve the flat tension performance of the honeycomb sandwich panel. Finally,the corresponding improvement methods and ideas are proposed for some problems in the research.
The composite sandwich structure is widely used in today's aviation industry because of its superior mechanical properties,but the traditional woven two-dimensional composite sandwich plate has poor resistance to delamination and peeling resistance in the thickness direction. As a new type of three-dimensional woven composite material,the looping fabric( U-cor) can effectively improve the mechanical properties of the composite sandwich structure in the thickness direction by pre-woven fabric loops. However,at present,there are few studies on the mechanical properties of the looped fabric reinforced sandwich structure in China. In this paper,the mechanical properties of flat-pulled honeycomb sandwich panels are studied. Firstly,a glass fiber looped fabric reinforced sandwich panel and a traditional glass fiber sandwich panel were fabricated by the vacuum bag forming process,and the flat pull test was completed. The force displacement curve and tensile strength were obtained. The test results show that the looped fabric reinforced honeycomb sandwich panel has a higher flat modulus and flat tensile strength. The main reason is that epoxy resin formed glue columns in the looped fabric panel during curing. The glue columns are involved in the stress of the core material to increase the tensile modulus,and the loops embedded in the glue columns also improves the flat tensile strength. It can be concluded that the loop fabric can effectively improve the flat tension performance of the honeycomb sandwich panel. Finally,the corresponding improvement methods and ideas are proposed for some problems in the research.
引文
[1]沈观林.复合材料力学[M].北京:清华大学出版社,2006.
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[4]Nanayakkara A,Feih S,Mouritz A P. Experimental analysis of the throughthickness compression properties of Z-pinned sandwich composites[J]. Compos Part A,2011,42(11):1673-80.
[5]Laine C,Grognec P L,Cardona S C,et al. Analytical,numerical and experimental study of the bifurcation and collapse behavior of a3D reinforced sandwich structure under through-thickness compression[J]. Int J Mech Sci.,2013,67:42-52.
[6]燕德利,周光明,王佳佳.起圈织物增强层合板层间力学性能有限元分析与试验研究[J].材料导报,2012,26(12):137-140.
[7]燕德利.起圈织物增强复合材料的细观结构和力学性能研究[D].南京:南京航空航天大学,2012.
[2]O'Brien T K,Paris I L. Exploratory investigation of failure mechanisms in transition regions between solid laminates and X-cor truss sandwich[J]. Compos Struct,2002,57:189-204.
[3]Marasco A I,Cartie D D R,Partridge I K,et al. Mechanical properties balance in novel Z-pinned sandwich panels:out-of-plane properties[J]. Compos Part A,2006,37(2):295-302.
[4]Nanayakkara A,Feih S,Mouritz A P. Experimental analysis of the throughthickness compression properties of Z-pinned sandwich composites[J]. Compos Part A,2011,42(11):1673-80.
[5]Laine C,Grognec P L,Cardona S C,et al. Analytical,numerical and experimental study of the bifurcation and collapse behavior of a3D reinforced sandwich structure under through-thickness compression[J]. Int J Mech Sci.,2013,67:42-52.
[6]燕德利,周光明,王佳佳.起圈织物增强层合板层间力学性能有限元分析与试验研究[J].材料导报,2012,26(12):137-140.
[7]燕德利.起圈织物增强复合材料的细观结构和力学性能研究[D].南京:南京航空航天大学,2012.