共查询到16条相似文献,搜索用时 897 毫秒
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通过建立轴对称有限元模型,对管板单边电阻点焊预压过程中电极与板以及板与管间接触行为进行了研究,系统分析了预压阶段接触区域范围及接触压力分布的影响因素.研究发现,管板焊接过程预压阶段的接触压力分布与传统点焊过程预压阶段接触压力分布有很大的不同.在电极和板以及板和管之间均形成环状接触区,可能导致焊后形成环状熔核;预压过程中,电极和板间接触区不受压力变化影响,板和管间接触区则受压力影响明显;接触区域大小和电极端面直径、管板厚度等因素均有关系.试验表明,所建模型的模拟结果与实际是相吻合的,为今后管板电阻点焊工艺参数优化及车身轻量化中管板厚度比优化提供有效依据. 相似文献
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针对管板单面电阻点焊工艺,建立其焊接过程的热、电、力耦合有限元分析模型,研究了焊接过程中的接触状态变化、温度场分布和焊接变形过程,揭示了环状熔核的生成机理,并利用金相试验和电极位移曲线对模型进行了验证.结果表明,计算结果与试验结果基本相符,证实了数值模型的正确性和适用性.研究结果可为管板单面点焊焊接机理和质量监控方法研... 相似文献
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以超高强淬火钢22MnB5搭接型点焊结构为研究对象,通过拉剪试验、光学试验和维氏硬度测试,获得了点焊结构的部分力学参数.在ANSYS中进行强度仿真,并与试验结果进行对比.结果表明,将点焊模型分为焊核、塑性环、母材三部分的有限元模型是合理的.同时仿真结果还表明点焊结构交界面的塑性环边缘处是最薄弱的位置,结构失效主要由切应力所引起,并分析了部分尺寸参数对结构强度的影响,当焊核半径、两板重叠长度与板厚越大,结构的最大Von Mises应力值就越低,但增大到一定程度后,其影响降低,为焊接工艺参数的优化提供参考. 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):609-617
AbstractAs a new kind of lightweight structure, hydroformed tubes are now widely used in vehicle bodies. The single sided spot welding (SSSW) is a variation of resistance welding used in joining hydroformed closed tubular parts and vehicle structures. During the process of SSSW, large deformation and complex contact status of the workpieces occur because there is no inside support. The time variation of the contact region and pressure distribution changes the flow paths for electric current timely and brings a fierce shunting at the position far away from the axis line, which prevents the heat concentration at the faying surface of workpieces. The characteristics of SSSW different from those of classical resistance welding mentioned above make it difficult to determine rational welding processing parameters for SSSW. In the present paper, a comprehensive structural–thermoelectric model is established. Using the incrementally coupled analysis of finite element analysis, the electrical, thermal and mechanical aspects of sheet to tube process using SSSW are investigated. The mechanical characteristic of specimens during the squeeze and welding progress, the electric current density transient distribution, the nugget formation process, and the effects of welding parameters for SSSW are discussed. It is found that ring nugget is obtained by sheet to tube SSSW. Modifying electrode force during welding cycle is a valid method to obtain acceptable nugget with shorter welding time or less energy. The calculated results of nugget size and location are in good agreement with those of experimental observations. 相似文献
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以结构负载压电传感的方式,研究借助声发射信号表征电阻点焊铝合金过程的熔核形核信息,包括焊接过程的声发射信号表征和熔核质量信息的声发射信号表征.结果表明,电阻点焊不论是稳定形核还是非稳定形核均可以用声发射信号来表征熔核形核的不同物理阶段.熔核形核的飞溅、开裂等特征事件也可以利用电阻点焊过程声发射信号的形核声发射特征参数来予以界定.声发射特征参数与熔核形核尺寸、焊点拉剪载荷具有较好的相关性.可以使用焊接过程中的声发射特征参数作为检测或预测熔核形核尺寸和焊点拉剪载荷的依据之一. 相似文献
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以TiO2粉末作为添加介质进行铝合金电阻点焊. 焊接过程中利用实时传感技术对电阻点焊熔核形核过程的电极电压与焊接电流信号进行实时检测,通过对检测信号的计算和分析得到熔核形核动态电阻曲线,研究TiO2粉末介质对熔核形核与生长过程电阻特征的影响. 结果表明,随着TiO2粉末介质的介入,熔核形核动态过程发生变化,表现出不同的动态电阻特征. 由动态电阻曲线提取的接触电阻、终了电阻和形核电阻热效应3个特征值均能反映TiO2粉末介质对熔核形核质量特征的影响,且终了电阻、形核电阻热与焊点最大承载力高度线性相关,可作为检测熔核形核质量的依据. 相似文献
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基于有限元理论建立了球形电极电阻点焊过程的电热力耦合模型,以ANSYS软件为平台分析了点焊的预压以及熔核的形成、长大及断电冷却过程。模拟得到了焊接过程中温度场、应力应变场的分布以及接触面积的变化,经过试验验证了所建电热力耦合模型的正确性。 相似文献
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建立了铝合金电阻点焊过程的有限元分析模型,采用基于显微接触理论的接触电阻模型模拟点焊过程中试件与试件界面上的接触电阻。计算获得了焊接过程中电极/试件和试件/试件接触界面上接触半径的变化,以及试件间界面上压应力、电流密度和温度的分布。试验考察了熔核的形成和长大过程。比较表明,计算与试验测量结果符合很好,证实了所采用的接触电阻模型在铝合金电阻点焊模拟中的正确性和适用性。 相似文献
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Resistance spot welding(RSW) is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure transformation of the base metal can be confined in the least limit. The material properties and the welding parameters have significant effects on thequality of the nugget. To predict the microstructure evolution in the melted zone and the heat-affected zone, an electrical, thermal, metallurgical and mechanical coupled finite element model is described and applied to simulate the welding process of the 6082 aluminum alloy. Experimental tests are also carried out. The comparison between experimental and numerical results shows that the adopted model is effective enough to well interpret and predict some important phenomena in terms of the phase transformation in spot welding of 6082 aluminum alloy. 相似文献