单搭压印连接接头的机械性能研究

发布时间：2018-05-28 14:40

本文选题：压印连接 + 有限元分析　；参考：《昆明理工大学》2011年硕士论文

【摘要】：能源和环境问题是制约世界经济发展的瓶颈,节能减排是解决这些问题的重要途径。为了减轻车身重量,新型材料(比如铝合金)的应用越来越广泛。由于铝具有高导热性和铝表面会形成天然氧化膜,很难用点焊进行连接。所以,需要一种新的连接技术来连接这些轻型材料。压印连接对于轻型材料的连接是一种简单高效的连接方法。本文主要运用有限元方法和试验方法研究单搭压印连接接头的机械性能,包括静态性能、动态性能和疲劳性能。为了得到精确的仿真结果,采用ANSYS和FE-SAFE软件进行联合仿真。静态分析和拉伸试验可以得出最大应力出现的位置以及压印连接接头破坏的方式：颈部断裂和底部剥离。静力分析为疲劳分析提供节点的应力应变信息。模态分析主要研究了影响固有频率的主要因素,固有频率随着杨氏模量的增长而显著增加；而泊松比对固有频率的影响很小。通过对模态振型的分析,可知横向振动的奇数振型关于两板搭接位置对称,并且搭接位置处在振型的峰值处；扭转振型的偶数振型两板搭接位置扭转严重,所以搭接接头的形状非常重要,而且对单搭压印连接结构的动态性能的影响很大。本文以铝合金2014-T6单搭压印连接接头的疲劳分析为例,叙述了ANSYS/FE-SAFE在疲劳分析中的应用和一般的分析过程。通过对不同系列铝合金压印连接接头的疲劳寿命对比,得出了铝合金2014-T6的疲劳性能最好,其次是AL2024-T351和AL5456-H311。对比了异种板材不同组合接头的疲劳性能,发现疲劳寿命相差很小。研究了表面粗糙度对疲劳寿命的影响,随着表面粗糙度值的增大疲劳寿命随之降低,并绘制了表面粗糙度与疲劳寿命关系曲线。研究了表面残余应力对疲劳寿命的影响,随着表面残余压应力的升高疲劳寿命随之升高,表面残余拉应力会对疲劳性能产生不利影响。
[Abstract]:Energy and environment are the bottleneck restricting the development of world economy. Energy saving and emission reduction are the important ways to solve these problems. In order to reduce body weight, new materials (such as aluminum alloy) are more and more widely used. Due to the high thermal conductivity of aluminum and the formation of natural oxide film on aluminum surface, it is difficult to connect by spot welding. Therefore, a new connection technology is needed to connect these lightweight materials. Imprint bonding is a simple and efficient bonding method for light-duty materials. In this paper, finite element method and test method are used to study the mechanical properties, including static, dynamic and fatigue properties of single lap imprint joint. In order to obtain accurate simulation results, ANSYS and FE-SAFE software are used for joint simulation. Static analysis and tensile test can obtain the position of maximum stress and the failure mode of imprint joint: neck fracture and bottom peeling. Static analysis provides the stress and strain information for fatigue analysis. Modal analysis mainly studies the main factors affecting the natural frequency, which increases significantly with the increase of Young's modulus, while the Poisson's ratio has little effect on the natural frequency. Through the analysis of modal mode, it can be seen that the odd vibration mode of transverse vibration is symmetrical about the two plates' lap position, and the lap position is at the peak value of the mode, and the torsion of even number vibration mode of torsional mode is serious. So the shape of lap joint is very important and has great influence on the dynamic performance of single lap imprint joint. Taking the fatigue analysis of aluminum alloy 2014-T6 single-lap joint as an example, the application and general analysis process of ANSYS/FE-SAFE in fatigue analysis are described. By comparing the fatigue life of different series of aluminum alloy imprinted joints, it is concluded that the fatigue properties of aluminum alloy 2014-T6 are the best, followed by AL2024-T351 and AL5456-H311. The fatigue properties of different composite joints of dissimilar plates are compared and it is found that the difference of fatigue life is very small. The influence of surface roughness on fatigue life is studied. With the increase of surface roughness value, the fatigue life decreases, and the relationship between surface roughness and fatigue life is drawn. The influence of surface residual stress on fatigue life is studied. The fatigue life increases with the increase of surface residual compressive stress, and the surface residual tensile stress will have a negative effect on fatigue performance.
【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

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