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复合材料开口补强实验研究和设计分析

【作者】 王毅

【导师】 岳珠峰;

【作者基本信息】 西北工业大学 , 工程力学, 2006, 硕士

【摘要】 由于飞行器结构设计的需要,复合材料开口补强问题,一直受到人们的重视,而且国内外已经开展了许多积极有效的工作。但是对于实际应用中出现的一些新情况,研究还存在一定的局限性。研究的内容多集中于复合材料薄板、小开口以及一些传统的补强工艺。本文旨在从力学与材料科学相结合角度针对复合材料开口问题的特点,采用理论分析、计算模型、实验考核与验证相结合的方法,开展了两种传统补强工艺在大开口、中厚板情况下的静力学性能分析,以及一种新补强方式的试验研究、有限元模拟、理论分析和参数设计等方面的工作。主要的工作总结如下: 1.为了对飞机中厚蒙皮设计中开口补强后的静力学性能进行研究,本文对复合材料开口问题的两种传统补强工艺翻边补强和二次共固化补强作用下中厚板的大开口问题进行了实验研究及有限元的模拟。结果发现,在这两种非对称补强工艺下,由于结构的几何不对称引起的偏心弯矩是结构失效的主要原因。 2.本文对一种新的补强方式--缝合补强进行了无缝合及五种不同的缝纫参数情况下缝合补强带孔板的静力学拉伸试验。结果发现,缝合前后试件的最终破坏载荷都很接近。并对其中的两组结果进行了有限元的模拟,缝纫的数值模拟是通过Ansys软件所提供的Link单元来实现的,通过对比发现,与实验结果吻合的很好。 3.为了给缝纫参数的设计提供依据,本文参照边界层理论以及最小余能原理,给出了孔边层间、面内应力的解析解。计算结果与他人的工作进行了对比,具有很高的可信性。 4.依照解析解的结果,并参照层合板的层间强度、缝线的相关弹性常数、孔边应力分析的平均应力准则以及缝线的拉伸强度等参数,本文提出了一种关于孔边距、缝线半径、针距这些补强设计所需要的缝纫参数的设计方法。并对其补强效果进行了有限元的校核,发现缝纫后孔边的层间应力分布有了明显改善。

【Abstract】 The question about the composite repair is regarded important for the need of aircraft design, and a large amount of study has been done in connection with it. But to some new case in practical application, our studies have limitation. In the previous study, focus at the laminate thin plane, small cut-out and some traditional reinforcement methods. In this paper, two kind of traditional reinforcement methods, and the work of the test and FEM study, paramate design about a new repair method have been studiedby the theoretic, numerical calculation and experiments. They are as follows:1. To carry out the static mechanics analysis of the repaired plate, the test and Finite Element Model (FEM) about composite medium thick plate with flange repaired and secondary cocure reinforcement have been completed.The resoult is that eccentric bending moment leaded by the physical dimension asymmetric is the prime reson of the structure failor.2. The statics tension test about the experiments of five kinds of reinforcement with different stitch parameters with respect to a new repaired means—stitch reinforcement and without any reinforcement have been completed. We find that the last failing load of these tests is likelihood. Used the Link Element given by Ansys to simulate the stitch threads, The FEM study about of two case have been completed. The resolute is perfect.3. To give a reference about the stitch parameter design, Based on the boundary -layer theory and the minimization complementary energy theory, the numerical resolute of interlaminar and innerlaminar stress near the edge have been given. The resolute have been Compaied with others, the conclusion is credibility.4. Based on the numerical resolute,consider the out-of-plane strength, the elastic characters and tension strength of the stitch thread ,refer to the average stress fracture criterion, those stitching parameter needed such as the distancebetween the edge and stitch line, the needle space, the stitch thread radius can be given. The resolutes of the repaired is checked by the FE. At last we find that the distribution of the out-plane stress of stitched laminate is improved as these stitch parameter be used through FE.

  • 【分类号】O346
  • 【被引频次】6
  • 【下载频次】511
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