全复合材料机翼的疲劳损伤容限分析

Abstract

As a new type of material, composite materials have been widely used in engineering field in recent years because of their excellent properties. The mechanical properties research of composite materials has made great achievements, but in the composite materials fatigue filed, more researchers use contents of the statistical and empirical formula to describe the change of the stiffness, strength and life, and they only consider one composite material, these studies are not applicable to any composite material.This article will begin with experiments of unidirectional composite and fabric, studying the basic mechanical properties and its results are generalized to composite laminated plate. Then these results are extended to the wing structure.Finally, a set of experimental design methods for damage tolerance of composite airfoil are established. Specific research contents are as follows: First, the basic mechanical experiments of the unidirectional composite and fabric composite materials were carried out to obtain the strength and stiffness under quasi-static conditions. Then tension by tension fatigue test has been carried, recording the phenomena in the test process, obtaining the fatigue life and drawing out the s-n curve.On the basis of fatigue test, the stiffness degradation of composite laminated plate and macro scale effect have been researched, the testing data are used as the foundation to study finite element simulation analysis of the wing structure.

Second, Considering two actual operating conditions when the wing is in service, the linear elastic analysis of the composite wing structure with finite element method is carried out, using two methods to get the corresponding fatigue life (Based on empirical formula established by the test data of arbitrary layer sequence composite and based on fatigue life prediction method with low - level simulation analysis for arbitrary laminated composite structures). In order to ensure the reliability of the results, the effect of fatigue notch coefficient on the fatigue life is further analyzed.

Finally, this paper introduces the methods and steps of damage tolerance analysis, and gives a method to compile fly-by-fly fatigue load spectrum for aircraft structure, using "mixed congruence method" to generalize random number which is used to randomly arrange the stress levels of aircraft structures.According to the result of the wing structure, the corresponding fatigue test fixture is designed, and its safety is analyzed by ABAQUS finite element software.

Keywords: composite material, fatigue life, wing structure, damage tolerance

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摘要......................................................................................................................I ABSTRACT ........................................................................................................... II 第1章绪论. (1)

1.1课题背景及研究的目的和意义 (1)

1.2国内外研究现状 (2)

1.2.1复合材料疲劳破坏机理研究 (2)

1.2.2复合材料疲劳力学性能的研究 (3)

1.2.3结构的损伤容限分析 (6)

1.3本文的主要研究内容 (7)

1.3.1基于复合材料疲劳实验数据的参数性能研究 (7)

1.3.2全复合材料机翼结构疲劳寿命预测 (8)

1.3.3全复合材料机翼结构损伤容限实验设计 (8)

第2章复合材料层合板实验研究及性能分析 (10)

2.1引言 (10)

2.2实验基础 (10)

2.3复合材料层合板的拉伸实验研究 (12)

2.3.1准静态拉伸实验 (12)

2.3.2拉-拉疲劳实验 (17)

2.4复合材料层合板的刚度退化研究 (19)

2.5复合材料层合板的宏观尺度效应研究 (21)

2.6本章小结 (24)

第3章全复合材料机翼结构的疲劳寿命研究 (25)

3.1引言 (25)

3.2全复合材料机翼结构模型 (25)

3.3全复合材料机翼结构静力分析 (27)

3.3.1机翼实际工况1 (27)

3.3.2机翼实际工况2 (30)

3.4全复合材料机翼结构的疲劳分析 (31)

3.5疲劳缺口系数的影响 (34)

3.6本章小结 (36)

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第4章机翼结构损伤容限实验设计 (38)

4.1引言 (38)

4.2损伤容限分析的方法和步骤 (38)

4.3疲劳载荷谱的编制 (40)

4.4机翼结构实验工装设计 (43)

4.5本章小结 (47)

结论 (49)

参考文献 (50)

哈尔滨工业大学学位论文原创性声明和使用权限 (53)

致谢 (54)

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