自冲铆接头动力学分析

发布时间：2018-11-13 13:04

【摘要】：自冲铆技术是一种冷成型技术,它由冲头将半空心铆钉压下刺穿上板在底板中呈喇叭状张开变形,在两层板或多层板中形成机械内锁。尽管自冲铆是一种新型的薄板连接技术,但是它的机械性能比传统的点焊好。自冲铆技术已在汽车行业得到广泛的应用,因此引起了其它工业领域广泛的兴趣。自冲铆技术被誉为下一代连接技术,是汽车轻量化过程中的一项关键技术。有限元方法及计算机技术的发展为研究它的成型过程及参数优化提供帮助,降低了研究成本。为了更好的了解自冲铆接头成型过程及对过程参数进行优化,本论文首先用数值方法及实验方法研究了自冲铆接头的成型过程。用动力学软件LS-DYNA基于Cowper-Symonds材料模型建立了2D轴对称模型,用Lagrange方法及r-自适应网格划分技术模拟了整个成型过程。结合实验的力-位移曲线及接头剖面图验证了模拟的合理性。分析了摩擦系数、过程成型时间、塑性应变比、自适应网格划分时间间隔等参数对成型的影响,摩擦系数直接影响自冲铆成型的质量。用ANSYS有限元软件对不同弹性模量与不同泊松比的组合及不同弹性模量与不同密度组合的情况进行了模态分析。研究了单搭自冲铆接头的自由振动情况,发现泊松比对单搭自冲铆接头的固有频率几乎没有影响；自冲铆接头的固有频率随着弹性模量的增加而增加,随着密度的增加而减小。在模态分析的基础上分析了自冲铆接头在外载荷激励下的响应状况及在冲击载荷下的瞬态性能。最后研究了自冲铆接头及自冲铆-粘复合接头的拉伸剪切试验,研究了其承载能力及破坏方式。从实验结果来看主要有两种破坏方式：铆头从下板中拉出及下板断裂。本文主要目的是实现自冲铆过程数值模拟及研究自冲铆接头动力学性能,为更深一步的研究提供基础。
[Abstract]:Self-punching riveting technology is a kind of cold forming technology, which press the semi-hollow rivets into the bottom plate by punching head and open and deform in the bottom plate, forming the mechanical internal lock in the two-layer or multi-layer plate. Although self-punching riveting is a new thin-plate bonding technology, its mechanical properties are better than that of traditional spot welding. Self-punching riveting technology has been widely used in automobile industry, so it has aroused wide interest in other industrial fields. Self-punching riveting technology is regarded as the next generation connection technology, and it is a key technology in the process of automobile lightweight. The development of finite element method and computer technology can help to study its forming process and parameter optimization, and reduce the research cost. In order to better understand the forming process of the self-punching riveting head and optimize the process parameters, this paper first studies the forming process of the self-punching riveting head by numerical method and experimental method. A 2D axisymmetric model based on Cowper-Symonds material model was established by using dynamic software LS-DYNA, and the whole forming process was simulated by Lagrange method and r-adaptive mesh generation technique. The rationality of the simulation is verified by combining the experimental force-displacement curve and the joint profile. The influence of the parameters such as friction coefficient, forming time, plastic strain ratio and self-adaptive mesh interval on the forming process is analyzed. The friction coefficient directly affects the quality of self-punching riveting. The combination of different elastic modulus and Poisson's ratio and the combination of different elastic modulus and different density were analyzed by ANSYS finite element software. It is found that Poisson's ratio has little effect on the natural frequency of single-lap self-punching riveting head, and the natural frequency of self-punched riveting head increases with the increase of elastic modulus and decreases with the increase of density. On the basis of modal analysis, the response of self-punching riveting head under external load and transient performance under impact load are analyzed. Finally, the tensile shear test of the self-punching riveting head and the self-punching rivet-bond composite joint is studied, and its bearing capacity and failure mode are studied. According to the experimental results, there are two main failure modes: the riveting head pulling out from the lower plate and the lower plate breaking. The main purpose of this paper is to realize the numerical simulation of the self-punching riveting process and to study the dynamic performance of the self-punching riveting head, which provides the basis for further research.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH131.1

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