汽车车身铝合金自冲铆接研究

发布时间：2018-03-22 19:08

本文选题：自冲铆接　切入点：铝合金　出处：《南昌大学》2017年硕士论文　论文类型：学位论文

【摘要】：汽车轻量化是汽车制造商当前以及未来发展的重点和主题,而汽车的传统用钢已不再适用于该主题,必须开发轻质合金和其它先进材料,当前轻质材料有铝合金、镁合金以及碳纤维材料等。铝材在汽车的应用上面临许多新的技术难题,自冲铆接是一种冷成型的连接方法,可以将铝合金等材质形成可靠的连接。然而,当前自冲铆接技术在我国汽车制造业中的研究和应用才有了初步的进展,影响自冲铆接接头质量的参数众多,但各个参数对接头质量的影响程度有待研究。本文以2mm厚度的AA5182-O铝合金作为半空心铆钉自冲铆接试验的研究对象,通过正交试验设计方法实现工艺参数的优化,并分析了铆模形状(平底铆模A、凸台铆模B和C)对自冲铆接接头力学性能的影响,研究了自冲铆接的疲劳性能,同时对自冲铆接力学性能与电阻点焊力学性能作了比较。具体如下:(1)以AA5182-O铝合金作为实验对象,采用正交试验设计方法,考虑铆模形状,预压力和铆接力三个因素,运用极差方法和方差方法分析了不同参数下的自冲铆接接头截面的自锁量、底部厚度、铆钉张开度、接头拉剪强度和十字拉伸强度的实验数据,结果表明:在三个因素中铆接力对自锁量的影响最大,但与自锁量不成相关性;而铆模形状对其影响次之,铆模凸台高度与自锁量成反比,铆模形状对接头拉剪强度和十字拉伸强度有显著的影响。在该基础上,获得了最佳的工艺参数。(2)在相同的预压力和铆接力,研究不同的铆模形状对自冲铆接接头的力学性能的影响。从拉剪和十字拉伸强度性能稳定性来看,平底铆模的最好。通过三种不同铆模的接头截面硬度测试发现,围绕着铆钉周围的材料塑性变形最大,而且铆模C对铝合金板材的变形影响最大。(3)对自冲铆接接头进行了疲劳实验,结果发现接头疲劳失效方式有三种分别是铆钉从下层板拔出、下层板断裂和上层板断裂。(4)对同种铝合金板材的自冲铆接和电阻点焊的力学性能进行比较,发现自冲铆接接头的拉剪强度、十字拉伸强度和剥离强度都要强于点焊接头,各个强度分别是点焊的1.27倍、1.37倍和1.68倍。而且自冲铆接接头的吸能高于点焊,更具有韧性。
[Abstract]:Automotive lightweight is the focus and theme of automobile manufacturers at present and in the future, and the traditional steel used in automobiles is no longer suitable for this theme. It is necessary to develop lightweight alloys and other advanced materials. At present, aluminum alloys are used in lightweight materials. Magnesium alloy and carbon fiber materials. Aluminum is faced with many new technical problems in the application of automobile. Self-punching riveting is a kind of cold forming bonding method, which can form reliable connection between aluminum alloy and other materials. At present, the research and application of self-punching riveting technology in China's automobile manufacturing industry has made a preliminary progress, and there are many parameters that affect the quality of self-punching riveting joints. However, the influence of various parameters on joint quality needs to be studied. In this paper, AA5182-O aluminum alloy with 2mm thickness is taken as the research object of semi-hollow rivet self-impact riveting test, and the process parameters are optimized by orthogonal design method. The influence of the shape of the riveting die (flat bottom riveting die, convex riveting die B and C) on the mechanical properties of the self-punching riveting joint is analyzed, and the fatigue properties of the self-punching riveting joint are studied. At the same time, the mechanical properties of self-punching riveting are compared with those of resistance spot welding. The following are as follows: (1) taking AA5182-O aluminum alloy as the experimental object, the orthogonal design method is used to consider three factors, such as the shape of riveting die, prepressure and riveting force. The experimental data of self-locking, bottom thickness, rivet opening, tensile shear strength and cross tensile strength of self-punching riveted joints under different parameters are analyzed by using the range method and variance method. The results show that the riveting force has the greatest influence on the self-locking quantity, but it has no correlation with the self-locking quantity, and the shape of the riveting die is the second, and the height of the punch is inversely proportional to the self-locking quantity. The shape of the riveting die has a significant effect on the tensile shear strength and cross tensile strength of the joint. The effects of different riveting die shapes on the mechanical properties of self-punching riveting joints are studied. The best one is the flat-bottom riveting die from the stability of tensile strength and cross tensile strength. The hardness test of joint section of three different riveting dies shows that, The material around rivets has the largest plastic deformation, and the riveting die C has the greatest influence on the deformation of aluminum alloy plate. The results show that there are three fatigue failure modes of joints: rivets drawn from the laminate, delamination of the laminates and fracture of the upper laminates. The mechanical properties of the same aluminum alloy plates are compared by self-punching riveting and resistance spot welding. It is found that the tensile shear strength, cross tensile strength and peeling strength of the self-impact riveting joint are all stronger than that of the spot welding joint, and each strength is 1.27 times of that of the spot welding, 1.37 times and 1.68 times of the spot welding respectively, and the absorption energy of the self-impact riveted joint is higher than that of the spot welding, and the strength is more toughness.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U466;TG938

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