A novel In-situ repair method of 7075 Al laminated interference-fit bolted joints under stress wave impact driven bushing cold expansion: numerical simulation and experimental validation

IF 8.3 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures Pub Date : 2026-04-13 DOI:10.1016/j.tws.2026.114975

Mengyang Cui , Duquan Zuo , Haolin Ding , Rongmin Tu , Yuqin Chen , Zhongbo Zhang , Chong Gao

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引用次数: 0

Abstract

Interference-fit bolted joints are easily damaged due to alternating load and overload impact, and their repair quality is directly related to the re-service safety of aircraft thin-walled structures. Aiming at the actual repair requirements of the shaking head part of the thin-walled connection area between the wing and the fuselage, this paper innovatively proposes a bushing cold expansion interference composite strengthening repair method based on stress wave impact loading. It establishes a finite element simulation model of the whole process of repairing the damaged joint of an Al single-lap thin-walled laminated structure. The accuracy and reliability of the model are verified by comparative tests and simulations. Furthermore, the evolution rules of indentation load, plastic deformation around the hole, strengthening area and microstructure characteristics under different expansion amounts were analyzed, and the unique advantages of the composite strengthening method in improving the repair quality of thin-walled joints were proved from multiple perspectives. The results indicate that a friction retardation effect occurs at the interface of the bushing hole wall during the composite strengthening process. Under the appropriate expansion amount, this effect helps to increase the residual compressive stress amplitude and its radial action depth. Under the optimal expansion amount of 2.0% (E₃), the distribution uniformity of residual compressive stress on the hole wall of the repaired part is the best, and the proportion of stress units is as high as 72.17%. The arc shape of the micro-grain boundary around the hole is moderate, the assembly gap is significantly reduced, and the exit tumor damage is slight. This fully confirms that the repair process of damaged joints can balance the strengthening effect and structural integrity by optimizing the expansion amount, to promote the transformation of residual tensile stress or zero stress unit on the hole wall to residual compressive stress, effectively inhibit the initiation and propagation of fatigue cracks, and realize the leap from geometric recovery to the structural integrity improvement of the repaired part.

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7075 Al层压干涉配合螺栓接头应力波冲击冷胀原位修复新方法：数值模拟与实验验证

干涉配合螺栓接头易受交变载荷和过载冲击而损坏，其修复质量直接关系到飞机薄壁结构的再使用安全性。针对翼机身薄壁连接区摇头部分的实际修复要求，创新性地提出了一种基于应力波冲击加载的衬套冷胀干涉复合材料强化修复方法。建立了铝单搭接薄壁层合结构损伤接头修复全过程的有限元模拟模型。通过对比试验和仿真验证了模型的准确性和可靠性。分析了不同膨胀量下压痕载荷、孔周塑性变形、强化面积及微观组织特征的演化规律，从多个角度证明了复合强化方法在提高薄壁接头修复质量方面的独特优势。结果表明：复合强化过程中，衬套孔壁界面处存在摩擦减速效应；在适当的膨胀量下，这种效应有助于增加残余压应力幅值及其径向作用深度。在最优膨胀量为2.0% （E3）时，修复件孔壁上残余压应力分布均匀性最好，应力单元占比高达72.17%。孔周围微晶界圆弧形状适中，装配间隙明显减小，出口肿瘤损伤轻微。这充分证实了损伤接头修复过程可以通过优化膨胀量来平衡加固效果和结构完整性，促进孔壁上残余拉应力或零应力单元向残余压应力的转变，有效抑制疲劳裂纹的萌生和扩展，实现被修复件从几何恢复到结构完整性提高的跨越。

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来源期刊

Thin-Walled Structures 工程技术-工程：土木

CiteScore

9.60

自引率

20.30%

发文量

801

审稿时长

66 days

期刊介绍： Thin-walled structures comprises an important and growing proportion of engineering construction with areas of application becoming increasingly diverse, ranging from aircraft, bridges, ships and oil rigs to storage vessels, industrial buildings and warehouses. Many factors, including cost and weight economy, new materials and processes and the growth of powerful methods of analysis have contributed to this growth, and led to the need for a journal which concentrates specifically on structures in which problems arise due to the thinness of the walls. This field includes cold– formed sections, plate and shell structures, reinforced plastics structures and aluminium structures, and is of importance in many branches of engineering. The primary criterion for consideration of papers in Thin–Walled Structures is that they must be concerned with thin–walled structures or the basic problems inherent in thin–walled structures. Provided this criterion is satisfied no restriction is placed on the type of construction, material or field of application. Papers on theory, experiment, design, etc., are published and it is expected that many papers will contain aspects of all three.