飞机复合材料阶梯式胶接结构的疲劳损伤与寿命

复合材料科学与工程 ›› 2020, Vol. 0 ›› Issue (2): 81-84.

飞机复合材料阶梯式胶接结构的疲劳损伤与寿命

曹双辉, 高弄玥, 刘斌^*

西北工业大学航空学院,西安710072

收稿日期:2019-04-22 出版日期:2020-02-28 发布日期:2020-02-28
通讯作者: 刘斌 (1986-),男,博士,主要从事复合材料力学方面的研究,binliu@nwpu.edu.cn。
作者简介:曹双辉(1998-),男,主要从事复合材料结构设计方面的研究。
基金资助:
陕西省自然科学基金(2018JQ1067);中央高校基本科研业务基金(3102017zy046)

FATIGUE DAMAGE PROPAGATION AND LIFE OF THE MULTI-STEPSBONDING STRUCTURE OF AIRCRAFT COMPOSITES

CAO Shuang-hui, GAO Nong-yue, LIU Bin^*

School of Aeronautics, Northwestern Polytechnical University, Xi′an 710072, China

Received:2019-04-22 Online:2020-02-28 Published:2020-02-28

摘要/Abstract

摘要： 随着复合材料胶接技术在飞机主承力结构上的广泛应用,阶梯式胶接形式由于在实际工程过程中易于实现而成为复合材料结构修理和连接的主要形式。目前文献多集中于研究金属、复合材料以及两种材料混合的单搭接结构的疲劳性能,但对于具有高效载荷传递的阶梯式结构的疲劳耐久性研究较少,其疲劳失效机制尚需厘清。本文对多级阶梯复合材料胶接结构进行了拉伸疲劳试验研究,应力比为0.1。在疲劳试验过程中观测了宏观裂纹的起始与扩展。根据试验数据拟合的S-N曲线,发现疲劳寿命随应力水平的增加而线性降低。在发现目视可见裂纹后至完全断裂,复合材料胶接结构仍具有10%的剩余寿命,说明当出现目视可见裂纹时,应及时维修或更换部件。从试样受力及破坏形式可知,复合材料胶接结构的剪切破坏是引起疲劳损伤的主要原因。通过阶梯状断口形貌分析,发现了内聚破坏、粘附破坏、基体开裂和分层四种典型破坏形式。

关键词: 复合材料, 阶梯, 胶接, 疲劳, 裂纹扩展

Abstract: Composites have been widely used as the main load-bearing structures′ material in aircraft, and among various structures, stepped topology has been chosen to become the main form of fuselage repairing and connection due to the easy implementation. Although a quantity of literature has given the fatigue performance of single-lap of metal, composite and two hybrids, the fatigue durability of the special multi-lap for high-efficiency load-transferring structure is seldom studied. Besides, the fatigue failure mechanism is still not illustrated adequately. In this research, the experiments on composite stepped-lap adhesively bonded structure, which is made under the process of mold making, prepreg clipping and laying firstly, autoclave solidification secondly, step surface brushing adhesive thirdly and finallycutting into specimens, were conducted. The cyclic tensile load of stress ratio 0.1 was selected in the experiment, and the visible cracks and propagation of fatigue testing process were detected through the experiments. All the specimens have been completely fractured at the end of the experiment in order to obtain the total life span. According to the linear curve fitted by S-N discrete based on the testing data, the fatigue life decreases linearly as the stress level increases. After visible cracks being found, the composite bonded structure only has 10% residual cracks expansion life until being completely fractured, which implies that the component must be repaired or replaced once visible cracks appear. For the cracking mechanism, composites matrix shear-mode damage dominates the fatigue initiation damage, while cohesive failure, adhesive failure, matrix crack, and delamination composed the fracture modes after stepped-surface fracture appearing.

Key words: composites, stepped-lap, adhesive, fatigue, cracks propagation

中图分类号:

TB332

曹双辉, 高弄玥, 刘斌. 飞机复合材料阶梯式胶接结构的疲劳损伤与寿命[J]. 复合材料科学与工程, 2020, 0(2): 81-84.

CAO Shuang-hui, GAO Nong-yue, LIU Bin. FATIGUE DAMAGE PROPAGATION AND LIFE OF THE MULTI-STEPSBONDING STRUCTURE OF AIRCRAFT COMPOSITES[J]. Composites Science and Engineering, 2020, 0(2): 81-84.

参考文献

[1] Abdel Wahab M M. Fatigue in adhesively bonded joints: A review. ISRN Materials Science, 2012: 1-25.
[2] 胡镇虎. 基于内聚力模型的复合材料胶接接头界面失效机理研究. 浙江: 浙江大学, 2018.
[3] FAA. Bonded repair size limits, PS-AIR-100-14-130-001. U. S. Department of Transportation, 2014, 12.
[4] Olajide S O, Arhatari B D. Recent progress on damage mechanisms in polymeric adhesively bonded high-performance composite joints under fatigue. International Journal of Fatigue, 2016, 95: 45-63.
[5] Zhang Y, Vassilopoulos A P, Keller T. Stiffness degradation and fatigue life prediction of adhesively-bonded joints for fiber-reinforced polymer composites. International Journal of Fatigue, 2008, 30(10-11): 1813-1820.
[6] Rudawska A, Abdel Wahab M M. The effect of cataphoretic and powder coatings on the strength and failure modes of EN AW-5754 aluminium alloy adhesive joints. International Journal of Adhesion and Adhesives, 2019, 89: 40-50.
[7] Wahab M M A, Hilmy I, Ashcroft I A, et al. Damage parameters of adhesive joints with general triaxiality, Part 2: Scarf joint analysis. Journal of Adhesion Science and Technology, 2011, 25(9): 925-947.
[8] Albedah A, Khan S M A, Benyahia F, et al. Experimental analysis of the fatigue life of repaired cracked plate in aluminum alloy 7075 with bonded composite patch. Engineering Fracture Mechanics, 2015, 145: 210-220.
[9] Chowdhury N M , Wang J , Chiu W K, et al. Experimental and finite element studies of thin bonded and hybrid carbon fibre double lap joints used in aircraft structures. Composites Part B Engineering, 2016, 100: 68-77.
[10] 郭霞, 关志东, 刘遂, 等. 搭接长度对复合材料单搭接胶接接头的影响. 科技导报, 2013, 31(7): 37-41.
[11] 梁祖典, 燕瑛, 张涛涛, 等. 复合材料单搭接胶接接头试验研究与数值模拟. 北京航空航天大学学报, 2014, 40(12): 1786-1792.
[12] 李波, 赵美英, 万小朋. 复合材料与金属胶接结构的次弯曲效应研究. 航空工程进展, 2013, 4(2): 170-174.
[13] 刘斌, 徐绯, 司源, 等. 飞机用复合材料斜胶接修补结构的冲击损伤. 复合材料学报, 2018, 35(10): 2698-2705.
[14] Liu B, Han Q, Zhong X P, et al. The impact damage and residual load capacity of composite stepped bonding repairs and joints. Composites Part B: Engineering, 2019, 158: 339-351.
[15] Wang C H, Venugopal V, Peng L. Stepped flush repairs for primary composite structures. The Journal of Adhesion, 2015, 91(1-2): 95-112.
[16] Liu B, Xu F, Feng W, et al. Experiment and design methods of composite scarf repair for primary-load bearing structures. Composites Part A: Applied Science and Manufacturing, 2016, 88: 27-38.
[17] Kim M K, Elder D J, Wang C H, et al. Interaction of laminate damage and adhesive disbonding in composite scarf joints subjected to combined in-plane loading and impact. Composite Structures, 2012, 94(3): 945-953.
[18] Wang C H, Gunnion A J. On the design methodology of scarf repairs to composite laminates. Composites Science and Technology, 2008, 68(1): 35-46.
[19] 彭海俊, 秦志文, 王继辉, 等. 胶接面纤维铺层角度对复合材料胶接应力和强度影响分析.玻璃钢/复合材料, 2017(4): 29-34.