飞机典型薄壁复合材料夹层结构整体屈曲

为了研究飞机机身无筋无框复合材料典型薄壁夹层结构在型号上应用的可行性，本文采用解析方法、有限元方法和试验方法对蜂窝夹层复合材料结构的面内压缩和剪切整体屈曲开展系统研究。基于经典层合板理论和工程解析方法推导蜂窝夹层复合材料的压缩和剪切屈曲载荷随试验件尺寸的变化规律。依据某型飞机机身典型结构分别设计压缩和剪切试验件尺寸大小、边界条件和加载方式。利用有限元商用软件ABAQUS对试验设计建立虚拟试验分析，对比验证解析方法和有限元方法的一致性。最后通过真实试验方法确定解析方法和有限元方法的有效性，并验证典型薄壁夹层结构的承载能力和破坏模式。结果显示，压缩试验结果失效模式与理论预测一致，故3种方法得到的结构整体失稳载荷相近，验证了理论方法的有效性；剪切试验结果发生局部破坏，故试验结果偏低，但有限元方法与解析方法所得结果一致，解析方法相对保守。

Overall buckling of typical thin-wall sandwich composites applied on the aircraft

In order to study the feasibility of applying typical thin-wall sandwich composite without ribs and frames reinforcement on the aircraft fuselage, overall buckling performance of the honeycomb sandwich composite under the in-plane compression and shear load was studied using analytical method, finite element method (FEM) and experiment. Based on the classical laminated plate theory and the engineering analytical method, the variation of the buckling load of honeycomb sandwich composites with the sample size was given and compared with the finite element results. Two typical sizes of sandwich structure were designed, and boundary conditions and loading methods were defined based on a certain type of typical aircraft fuselage structure. Finally, the buckling loads obtained by analytic solution and FEM were compared with the experimental results, which verified the bearing capacity and failure mode of the typical thin-wall sandwich structure. The results show that the test compression failure mode is consistent with the theoretical prediction, so the overall buckling load calculated through the three methods is almost equal to each other. Because local failures occur in the shear test, so the experimental result is lower than FEM result and analytic result. However, the FEM results and the analytical results are consistent, which could verify their effectiveness. And it's found that the analytical method is relatively conservative.