基于对称加载的均匀干涉配合铆接方法

铆接干涉量均匀度是影响飞行器装配接头疲劳寿命、结构铆接变形的重要因素之一。为了提高铆接干涉量均匀度,采用基于应力波加载的电磁铆接双面铆接方法,对对称加载的铆接工艺方法进行了研究。利用应力波传播和叠加原理对对称加载的钉杆应力水平进行理论分析,试验测量了电磁力应力波及其叠加效应。通过工艺试验和微观分析,研究了对称加载方法对铆接质量的影响。研究结果表明:对称加载方法下,双向应力波同步触发,脉冲宽度相等,钉杆理论应力水平高于单面加载;在对称应力波作用下,整体钉杆干涉量均匀,并形成有效干涉,钉头与夹层贴合紧密;对称加载钉孔绝对干涉量更大,平均干涉量大于单面加载14%,干涉量均匀度高出单面加载37.5%,有利于实现连接结构的疲劳寿命增益;对称加载方法引起的结构件铆接变形量小于单面加载,更容易保证装配件外形准确度。

Interference-fit evenness riveting method based on symmetrical loading

Evenness of riveting interference plays an important role in fatigue life of aircraft assembly joints, which is also one of the main reasons causing riveting structure deformation. With the purpose of improving the evenness of riveting interference, a research on symmetrical loading riveting process method is carried out, based on the symmetrical electromagnetic riveting with stress wave loading. In this paper, the rivet theoretical stress level under symmetrical loading is derived through propagation and superposition principle of stress wave, and electromagnetic guns' stress wave and superposition principle of stress wave are recorded through the experiment. With the riveting experiments and micro-analysis of riveting structure, the riveting quality is also studied under symmetrical loading. The results show that under symmetrical loading, the stress waves of two riveting guns simultaneously trigger with the same pulse length, and the rivet theoretical stress level is higher than that under uniaxial loading. Under the symmetrical stress wave loading, the overall deformation of rivet is uniform, forming an effective interference through the whole rivet, and rivet head and interlayer joint closely. The average level of interference is larger than the interference under uniaxial loading by 14%. Moreover, the average interference evenness increases by 37.5% under symmetrical loading which makes for achieving high fatigue life of aircraft assembly joints. The riveting structure deformation is smaller under symmetrical loading, doing good to ensure assembly accuracy.