【作者】 董标；

【导师】 何晓聪；

【作者基本信息】 昆明理工大学 ， 机械制造及其自动化， 2011， 硕士

【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。更多还原

【Abstract】 The Self piercing riveting (SPR) is a cold forming process, in which a semi-tubular rivet pressed by a punch pierces the upper sheet and flares in the bottom sheet, and creates a strong mechanical interlock between two or more sheets. Although SPR is a new sheet material joining technique, its mechanical behaviour is better than traditional spot weld technique, SPR has been using widely in automobile industry and catch more attention from many other industrial fields. The SPR can be called the next generation joining technology and used as the a key technique in the automobile light weight. Finite element method (FEM) and computer development do a great favor of the study of SPR and its optimization of the parameters and make the cost of study down.In order to understand the process of SPR better and optimize the parameters of the process, the SPR process was studied numerically and experimentally firstly in this thesis. A 2D axisymmetric model was generated based on Cowper-Symonds material model in LS-DYNA FEM software, Lagrange method and r-adaptivity method was employed during the simulation process. According to the force-displacement curve and the cross-section of SPR joint, it can be seen that it can be seen that the simulation results were in good agreement with the experimental results. The parameters of friction, forming time, plastic strain to failure and Time interval between adaptive refinements was studied, it can conclude that the quality of SPR is affected directly by friction.Dynamic behavior of SPR joints of different Yong’s modulus versus Passion’s ratio and different Yong’s modulus versus density was studied using ANSYS code. It could be found that the natural frequencies of SPR joint change slightly with the Passion’s ratio varying, but increase as the Yong’s modulus of sheets increase, decrease as the density of sheet increase.The response with the inspired load and the transient behavior of SPR joint was studied based on the modal analysis.The tensile experiments of the SPR joint and SPR-Adhesives hybrid joint were conducted in order to get the tensile capacity and failure models. It is observed that there are two main failure modes:rivet pulled out of bottom sheet and bottom sheet fracture. This thesis aims to achieve the simulation of SPR process and studies the dynamic behavior of SPR joint and as a basis for further research.更多还原