单搭压印连接接头的机械性能分析张文斌.docVIP

单搭压印连接接头的机械性能研究 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和密度的增长而显著增加；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，随着表面粗糙度的升高疲劳寿命随之降低，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。 关键词：压印连接；有限元分析；疲劳分析；ANSYS/FE-SAFE  Mechanical Properties of Single Lap-jointed Clinched Joints Abstract Energy and environment problems are the bottleneck that restricts world economy progress. The work of energy saving and emission reduction is an important way to solve related problems. The use of lightweight materials such as aluminium alloys has increased to reduce the weight of the automobile body. But it is difficult to join aluminium by welding because of its high thermal conductivity and the natural surface oxide layer. Hence, a new method is required to joint these lightweight materials. Clinching technology is an efficient method of connection for lightweight materials. In this paper, the mechanical properties of single lap-jointed clinched joints were studied based on FEM and test, including the static behaviour, dynamic behaviour and fatigue behaviour. In order to get accurate simulation results, the joint simulation method of ANSYS and FE-SAFE was used to make these analyses. The static analysis indicates the maximum stress and its position in clinched joints. The tensile tests reveal that there are two main modes: neck fracture mode and button separation mode. Static analysis provides the information