【作者】 陈军；

【导师】 成艾国；

【作者基本信息】 湖南大学 ， 车辆工程， 2012， 硕士

【摘要】 点焊是现代车身制造中应用最广泛的工艺，以有限元法为主的CAE技术，是汽车设计由经验设计转变为科学设计必不可少的一项重要技术。在应用通用有限元分析软件进行车身分析计算中，车身钣金件容易用具有薄膜及弯曲效应的壳单元进行描述，而焊点本身却不易模拟。对于由成千上万个分布的焊点连接而成的车身来说，点焊结构的有限元模型建模技术，是保证计算结果正确并有较高精度的关键技术。本文首先介绍了汽车制造中焊接技术的现状及发展趋势，说明点焊在当今国内汽车生产过程中的应用情况及其优越性。然后主要针对点焊本身的特性、点焊的失效、特定的焊接母材特性进行分析，并对比几种不同点焊模拟方式的仿真精度，最后对DYNA中两种常用的点焊模拟方式（beam和solid）进行稳健性分析得出相应结论。在汽车整车正面碰撞仿真分析中，白车身的结构完整性至关重要，而白车身基本是通过点焊进行连接，因此，点焊的仿真模拟方式在汽车碰撞过程中极为重要，本文通过Lap-shear、Coach-peel、U-tension三种点焊样件模型分析几种点焊模拟方式的精度，得出beam及solid两种点焊模拟方式的仿真精度接近，从而从不同角度切入，通过模拟仿真对传统的Lap-Shear模型及改进后的Lap-Shear模型对比研究beam焊点单元和solid焊点单元的特性，分析两种不同点焊模拟方式对单元积分方式及点焊相对网格单元位置的稳健性高低，最终通过某微型车的正面碰撞进行试验验证。论文的分析结果表明：通过分析两种不同点焊模拟方式对单元积分方式及点焊相对网格单元位置的稳健性，以及某微型车的正面碰撞试验验证，得出solid焊点模拟方式的仿真精度高，能有效的模拟焊点失效，对在前期整车研发过程中的碰撞仿真有着重要的指导作用。更多还原

【Abstract】 Spot weld is the most widely used technology in the modern bodywork. The CAEtechnology based on finite element method is an important technology in automotivedesign changed from experience design to scientific design. While usinggeneral-purpose finite element analysis software carried on calculation of bodyanalysis, the body sheet metal is easy to be described using shell element withmembrane and bending effects, but the spot weld itself is not easy to simulate. For thebody connected whit thousands of distribution of the spot weld, the finite elementmodeling technology of spot weld structure is the key technology ensuring that thecalculations is correct and accuracy.This paper first introduces the status and development trends of weldingtechnology in the automobile manufacturing, and instructs the application andadvantages of spot welding in today ’s domestic automobile production process, andthen mainly analyze spot welding characteristics, spot weld failure, specific weldingbase metal properties, and compare the simulation accuracy of the simulation methodof several different spot welding. Finally robustness is analyzed on two common spotwelding simulation methods in DYNA (beam and solid) and then gets thecorresponding results.In the auto frontal crash simulation analysis, the structural integrity of the whitebody is very important, and white body is connected through spot welding, therefore,spot welding simulation method in car collision is very important, this paper throughthe Lap-shear, Coach-peel, U-tension three spot welding sample model analysis theprecision of several spot welding simulation methods, and concludes that the simulatedaccuracy of beam is close to that of solid, and from different perspectives, through thesimulation to the traditional Lap-shear model and the improved Lap-shear model beamcontrast research characteristic of beam spot welding unit and solid spot welding unit,analyzing how the robustness is about two kinds of different spot welding simulationmethod to the grid unit integral way and spot welding unit’s relative position to thegrid unit, finally it is validated through a mini car frontal crash test.The paper’s analysis showed that the robustness of the relative element integralway and spot welding spot welding simulation of two different grid cell location, aswell as a mini-car frontal crash test verification, the simulation of the solid solder joint simulation approach high precision, can effectively simulate the solder joint failure,has an important guiding role in the crash simulation in the early vehicle developmentprocess.更多还原