共查询到18条相似文献,搜索用时 621 毫秒
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高速列车采用超长铝合金型材作为车身新材料。搅拌摩擦焊以固相连接原理成为高铁车身制造新工艺。针对单热源模型不足,考虑搅拌轴肩转动摩擦生热和搅拌头塑变剪切生热,建立搅拌摩擦焊双热源有限元模型。基于传统熔焊方式,实现满足搅拌焊特征的双面挤压型材接头变形设计。通过ANSYS二次开发,完成该工艺移动瞬态热交换数值仿真,获得焊接全程三维温度场分布,仿真结果与试验数据吻合良好。结果表明,该仿真模型可行.仿真结果合理,为高铁车身国产化制造工艺吸收和工艺优化提供参考。 相似文献
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《热加工工艺》2021,(1)
为了研究DP590钢和AA6061-T6铝合金异种金属对接搅拌摩擦焊工艺参数对温度场的影响,优化实际焊接时工艺参数的可选择范围,首先建立了异种金属对接搅拌摩擦焊搅拌头摩擦生热的热输入模型,然后运用ABAQUS软件模拟出DP590钢和AA6061-T6铝合金对接搅拌摩擦焊的温度场,研究焊接过程中异种板材温度场的分布规律,最后通过调整焊接参数模拟出接头的温度分布,对比分析搅拌头偏置位置、焊接参数对接头温度场的影响。结果表明:钢铝异种金属对接搅拌摩擦焊焊接过程中的最高温度处位于DP590钢板侧,搅拌针偏置主要影响钢板的温度分布,搅拌头转速是影响焊接接头温度场的主要因素。 相似文献
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为更贴近实际的模拟搅拌摩擦焊焊接过程中复杂的热力行为,试验通过建立三维搅拌摩擦焊过程数学模型,采用三维实体耦合的有限元方法来分析2219铝合金搅拌摩擦焊热过程和温度场分布.结果表明,搅拌摩擦焊焊缝的温度场梯度呈现上密下疏,前密后疏的分布状态,最高温度位于后退侧的搅拌针与轴肩的过渡区,焊缝后退边的温度高于前进边,搅拌针底部温度超过2219铝合金的再结晶温度,可确保对接接头根部形成紧密焊缝,模拟结果为研究搅拌摩擦焊的机理和优化搅拌摩擦焊焊接工艺提供了支持. 相似文献
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根据搅拌摩擦连接特点,充分考虑搅拌摩擦连接过程中搅拌针各部位与连接板材之间的摩擦生热及在连接过程中连接板材摩擦系数随温度变化规律,建立了适合搅拌摩擦连接自身特点的动态热元模型,并利用此模型进行了航空铝合金板材搅拌摩擦连接过程的有限元分析模拟.通过模拟结果和试验结果对比验证了所建立的动态热源模型和有限元分析过程是合理的.模拟结果显示搅拌摩擦连接残余拉应力主要集中在连接区,且在连接区中间位置出现最大残余拉应力区,连接区两端及其它部位出现残余压应力. 相似文献
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Wu ChuansongSu HaoShi Lei 《金属学报》2018,(2):265-277
The heat generation, heat transfer and plasticized material flow in friction stir welding determine directly the microstructure evolution and mechanical properties of weld joints. Numerical simulation of these thermo-physical phenomena is of great significance for getting a deep insight into the underlying mechanisms and optimizing the process parameters of friction stir welding. This article reviews the progress status in numerical simulation of heat generation, heat transfer and plasticized material flow behaviors in friction stir welding, and outlines the unsolved problems. The research work targeting these issues, which has been conducted by the authors' group, is introduced. According to the stress characteristics at the tool-workpiece interface, the expressions of sticking rate and friction coefficient are developed, and this measurement-calculation method lays foundation for improving the accuracy of numerical analysis. Through synthetically considering the characteristics of complex-shaped tools, a three dimensional model of friction stir welding process is established. Three types of tools are taken into consideration, i.e., normal CT (conical-pin tool), ST (conical-pin with 4 flats tool) and TT (conical-pin with 3 flats tool). For the cases in application of these tools, the heat generation, temperature profile, and material flow velocity are analyzed quantitatively. A mathematical model for the whole friction stir welding process including plunge stage, dwell stage, welding stage, and cooling stage is established for numerical analysis of transient development in heat generation rate, temperature and material flow fields in each stages. Based on the status review, the trend in numerical simulation of frictions stir welding is outlooked, and the research focus for next step is proposed. 相似文献
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Macrostructures and mechanical properties of ultrasonic-assisted friction stir welding joint of 2024-T3 aluminium alloy 下载免费PDF全文
In friction stir welding of aluminum alloys, tunnel defect may occur due to insufficient plastic material flow caused by lower heat input in the weld region. The inadequacy in heat input is due to improper selection of friction stir welding tool and process parameters. Ultimately, such defects degrade the properties of weld and may pose serious concerns towards the integrity and safety of the weld component. In order to improve the properties of weld joints, an ultrasonic-assisted friction stir welding device has been configured where ultrasonic energy is transferred from an ultrasonic unit directly into one of the workpieces near the tool. Using this configuration, ultrasonic-assisted friction stir welding was conducted on 6 mm thick 2024-T3 aluminum alloy sheets. The macrostructure and mechanical properties of these welds were compared with the welds of this alloy prepared by conventional friction stir welding using identical process parameters. The results show that the welding speed can be increased while satisfactory weld quality is still ensured. The ultrasonic energy transferred in this configuration could enlarge the volume of weld nugget zone. Also, the influence of ultrasonic energy on the suppression or elimination of the tunnel defect is quite apparent. However, any beneficial effects of ultrasonic vibration on the tensile strength and the elongation of the joint were less obvious in this configuration. 相似文献
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为探究搅拌头几何形貌对2219铝合金厚板搅拌摩擦焊核心区温度场的影响,基于ABAQUS/CEL建立了18 mm厚2219铝合金FSW三维过程仿真模型,应用有限元分析法对焊接过程进行仿真研究,得到了焊接核心区测温点实时温度循环曲线。利用自主研发的热电偶测温系统对焊接温度场相应测温点温度进行检测,经过对比可知,不同转速试验和仿真数据曲线变化趋势基本相同,验证了所建立的FSW过程仿真模型的有效性。探究了搅拌头结构参数对FSW过程核心温度场的影响规律,针对搅拌头的轴肩尺寸、搅拌针锥角、轴肩凹角、螺纹升角等结构尺寸设计了4因素3水平正交试验。结果表明,轴肩直径对核心区温差的影响最为显著,当搅拌头的轴肩尺寸为36 mm、搅拌针锥角为6°、轴肩凹角为2.5°、螺纹升角为11°时,搅拌头结构尺寸较为合理,核心区温差值较小。
创新点: 探究了搅拌头几何形貌对搅拌摩擦焊核心区温度场的影响,实现了搅拌头的结构参数优化。 相似文献
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2024铝合金板搅拌摩擦焊接塑性材料流动的可视化检测与数值模拟(英文) 总被引:3,自引:0,他引:3
将薄铜片作为标示材料镶嵌于2024铝合金板中,经搅拌摩擦焊接焊后,用金相法观察其最终位置。参考材料流动的可视化实验结果,建立搅拌摩擦焊传热与材料流动的三维数值分析模型。搅拌针附近塑性材料流动速度分布模式的计算结果与可视化实验结果基本一致。当焊接速度一定时,随搅拌针旋转速度的提高,搅拌针附近塑性材料流动加剧。焊核区形状与尺寸的计算结果与实测数据吻合。 相似文献
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基于CEL模型的搅拌摩擦焊接7055铝合金仿真模拟 总被引:1,自引:0,他引:1
基于耦合的欧拉—拉格朗日(CEL)模型,建立了高可靠性、高精度的搅拌摩擦焊7055铝合金热力耦合计算模型,开展了焊接工艺参数对7055铝合金焊接接头温度、等效应变以及缺陷预测结果的影响规律的研究,并分析和讨论了搅拌摩擦焊试验验证模拟结果的可靠性. 7055铝合金搅拌摩擦焊CEL模型预测结果表明,温度和等效塑性应变与转速呈正比,与焊接速度呈反比,这主要与焊接工艺参数影响轴肩与7055铝合金的摩擦生热及材料的流动,使焊接温度和等效塑性应变值发生变化有关.当焊接速度在60 ? 300 mm/min、转速在300 ? 1 200 r/min范围内,焊接温度均低于7055铝合金熔点,当焊接速度增加到300 mm/min时,由于产热不足,温度和等效塑性应变均降低,此时在焊接接头处容易产生孔洞缺陷.7055铝合金搅拌摩擦焊试验结果表明,当转速为600 r/min、焊接速度为180 mm/min时,7055铝合金接头组织致密,接头抗拉强度达到489 MPa,断后伸长率为4.0%.当焊接速度提高至300 mm/min时,接头抗拉强度为411 MPa,断后伸长率仅为1.0%.这与产热不足导致接头处结合较差有关,与模拟结果一致. 相似文献
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超声辅助搅拌摩擦焊是一项在搅拌摩擦焊的搅拌头上添加轴向高频振动的新技术. 以6 mm厚7075铝合金材料为研究对象,建立了超声辅助搅拌摩擦焊与普通搅拌摩擦焊接的热源模型,通过ANSYS软件研究了轴向振动对焊接过程温度场以及焊后残余应力的影响规律. 结果表明,轴向振动的添加能够增大热输入量,提高焊接峰值温度且降低焊缝残余应力;在相同转速及焊接速度下,当振动频率一定时,焊接峰值温度和焊后残余应力随着振动幅值的增加而增大;当振动幅值一定时,随着振动频率的增大,焊接峰值温度及焊后残余应力也相应增加. 相似文献
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根据搅拌摩擦焊特点及库伦摩擦做功理论,以厚度为6 mm的7075-T7351铝合金板材为研究对象,基于ANSYS有限元软件,建立了搅拌摩擦焊双热源三维有限元模型,研究不同转速、焊接速度对温度场及残余应力场的影响规律.结果表明,焊接过程峰值温度在500℃左右,接头最高温度出现在搅拌头后部大约5 mm处;接头残余应力以纵向残余应力为主,在垂直焊缝方向上呈M形分布,最大值约为150 MPa;当搅拌头转速一定时,随着焊接速度的增大,峰值温度减小,峰值纵向残余应力增大;当焊接速度一定时,温度随着转速的增大而增大,且转速越大,纵向残余应力分布越均匀. 相似文献