【作者】 叶茂；

【导师】 罗震；

【作者基本信息】 天津大学 ， 材料加工工程， 2006， 硕士

【摘要】 本课题首先提出了电阻点焊熔核设计这个概念:从电阻点焊产品的实际承载出发,并利用PC及有限元软件进行虚拟设计和虚拟实验,在实际生产之前模拟设计出能够得到合格熔核的电阻点焊参数。本文围绕电阻点焊熔核设计这个核心,具体的提出设计步骤:首先通过对点焊接头的功能和工况进行分析,得到点焊熔核的承载情况。然后对熔核进行受力分析,得出合格的——能够满足设计要求的熔核尺寸数据(熔核直径和焊透率)。最后进行虚拟实验,依据建立的点焊熔核形成过程的有限元数值模拟模型,模拟设计出一个熔核,将其与合格的点焊熔核比较,获得具有参考价值的点焊工艺参数。本课题是从反方向来研究和分析电阻点焊,这种方法和传统方法有两个区别,一个是在熔核设计阶段,区别于传统先有熔核再来确定熔核形状及尺寸,而是根据工程需要确定熔核尺寸并设计出熔核形状,进而确定出具体的熔核;二是在熔核形成的过程中,区别于传统的通过多次调整点焊工艺参数来获得合格熔核的方法,而是采用通过合格熔核反向推导出多组点焊焊接工艺参数,从中选出符合实际生产条件的点焊焊接循环参数。本文采用ANSYS有限元软件,依据低碳钢薄板焊接材料的物理性能参数,建立了点焊熔核拉伸剪切受力分析模型和熔核形成过程的热-电-力耦合模型。利用开发生成的ANSYS命令流,对整个设计过程进行多次模拟实验,获得了点焊模拟实验数据。本文根据建立的点焊熔核拉伸剪切受力分析模型,计算分析了在承受同样载荷的条件下,圆柱型熔核、椭球形熔核和圆台形熔核的应力状况,确定圆台形熔核的受力情况更接近实际情况,并将其做为模拟设计和判定用的熔核。在电阻点焊形核过程的数值模拟中,通过对数值模拟得到的温度场数据进行处理,获得了能够表征熔核尺寸的数据,建立了联系温度场和熔核尺寸的桥梁。并且把模拟设计出来的熔核与合格熔核进行对比,确定了能够生成合格熔核的工艺参数。虽然本文提供的数值模拟模型及实验并不能够完全替代实际的模型及实验过程,但是它做为电阻点焊研究的有效手段,可灵活地对电阻焊过程中的各种影响因素进行研究,帮助人们进行一些通过试验而不可能完成的研究和分析,为电阻焊研究提供理论上的指导更多还原

【Abstract】 This paper firstly offers a new conception. It is the Designing of Resistance Spot Welding Molten Core that according to the real load to the molten core of RSW, the researchers use PC and the finite element program, to get a qualified molten core with necessary parameters and some welding parameters for imputing to the RSW equipment by the means of numerical simulation designing bfore manufacture. The phases of designing are also discussed in this paper: firstly, the real load to the molten core of RSW should be clear through analyzing the part’s function and work condition. Secondly, establishing a finite element numerical simulation model is indispensable to calculate and analyse to get a qualified molten core with necessary parameters. Thirdly, a thermal-electric-mechanical finite element model is constituted to simulate the process of RSW and creat a molten core to compare with the qualified one to make the datum for imputing sure.The ANSYS application program is used in this paper to creat the finite element and analysis. According to the mild steel’s material physical properties, tow models are created in this paper. The one is a 3D solid model to simulate the cutting process of molten core; the other is a 2D axisymmetric coupling model to simulate the process of creating a molten core. Both models are used to calculate and anaylyse in order to get necessary datum.Several types of molten core are calculated and analyzed in this paper under the same condition. Compare every type of model‘s analysis datum got, the model with a truncated cone shape is closer to the reality, and best to use as a standard molten core shape to compare with the one got through the process of creating.Temperature field is always used to describe the shape of molten core in RSW numerical simulation. This paper also discusses the relationship between the molten core shapes and the temperature filed. Comparing the standard molten core shape with the creating one, some welding parameters can be confirmed to creat a real molten core.Though the models and the ways of numerical simulation can not replace the real experiment, it is a predictive tool reducing the number of experiments for the optimization of welding parameters.更多还原