NACA构型泡沫夹层复合材料空气风门的结构强度分析

泡沫夹层复合材料具有比强度、比刚度大,保温隔热性能优异等优点,广泛应用于航空航天等诸多领域,在飞机上则应用于一些载荷不大而厚度较小的部件或结构。研究的NACA构型泡沫夹层复合材料空气风门以其材料的特殊性,在组合工况下受力情况复杂,目前对其在多工况下进行强度分析的相关研究较少。以NACA构型的泡沫夹层碳纤维复合材料空气风门为研究对象,建立了有限元模型。通过重点对多工况下风门壳体的等效应力分布情况进行对比和分析,并对夹层结构各层的应力危险区域进行强度校核,得到了各工况下复合材料面板层和泡沫芯材层的应力敏感区域和失效情况,以及载荷对模型应力影响的规律。

STRENGTH ANALYSIS OF NACA COMPOSITE AIR INLET WITH FOAM SANDWICH STRUCTURE

Because of its high strength-weight ratio and modulus-weight ratio,excellent thermal insulation performance,the foam sandwich composite has been widely used in aerospace industry.On airplane,it's applied to some structures which are thin in thickness and bear small loads.Due to its particularity in material,the stress conditions of NACA carbon fiber reinforced composite air inlet with foam sandwich structure is rather complex under combined loads.As a result,there are few studies on the strength analysis of this kind of NACA air inlet so far.In this paper,the NACA composite air inlet with foam sandwich structure was selected as the study subject,and its finite element modeling was built.By analyzing and comparing the equivalent stress contours of the air inlet's shell in different cases,along with checking the strength in stress concentration areas of the sandwich structure's each layer,failures of foam core and composite skins were examined,and regularities about influences of loads on the air inlet were figured out.The results indicate that the stress concentrated areas of the composite layer are near the bolt holes,and for the foam layer they are near the joint regions between valve plates and shell of the air inlet.And,based on the results of finite element calculation,the foam would be destroyed under some extreme working-conditions.So foam with better properties should be adopted or stress concentrated areas of the foam layer should be reinforced.