共查询到20条相似文献,搜索用时 390 毫秒
1.
2.
焊接时焊缝及其附近因热膨胀受到周围温度较低金属的拘束,产生大量的压缩塑性应变(简称残余塑变),残余塑变的大小和分布决定了最终的残余应力和变形。副车架的焊接变形对汽车底盘的制造精度和质量有重要的影响。本文用残余塑变法对别克轿车副车架焊接总成时,连接前梁、后梁、左梁和右梁的21条焊缝焊接以后的变形规律进行了有限元建模与分析。计算采用了两种大小的有限元网格尺寸,结果表明,对副车架焊接变形分析,焊缝附近大小为15mm的网格尺寸是合理的。所得焊接变形的有关数据可供焊接工艺设计时的预留变形量、工艺参数以及夹具设计等参考,从而保证底盘件的焊接精度和质量。 相似文献
3.
减少车架焊接变形的措施周伟天津本田摩托有限公司(300221)我公司生产的TH90摩托车的车架是一个由钢管及钢板组成的摇篮式空间焊接结构(如图)。随着大批量生产而出现的车架焊接超差变形,给后序的整车装配带来了麻烦,而且对于刚度较大的车架进行返修矫正也... 相似文献
4.
《热加工工艺》2016,(9)
针对某型号A356铸铝前副车架,采用直流脉冲焊方法,以ER5554焊丝作为填充材料进行了焊接工艺试验研究并实现了局部1∶1模拟接头的连接。针对局部1∶1模拟接头设计了相应的焊接试验方案,研究了焊接电流、焊接速度、拼接间隙等工艺参数对焊接质量的影响规律,在此基础上针对局部1∶1模拟接头测试了相关的力学性能。结果表明,焊接电流、焊接速度与拼接间隙对焊缝熔宽、余高与根部侧壁熔合有显著影响;间隙对焊缝根部侧壁熔合影响最大,过小的间隙容易造成焊缝根部未熔合,极大地降低接头抗拉强度。研究结果为实现铸铝副车架替代钢制副车架提供了连接技术方面理论指导,有较好的工业应用价值。 相似文献
5.
6.
针对手动液压搬运车车架主焊工序双机器人同步焊接路径规划问题,文中引入虚拟点将多旅行商问题转化为单旅行商问题,选用换位表达编码方式对车架焊缝编码,然后采用基于状态转移策略的人工蜂群算法建立双机器人同步焊接数学模型,仿真求解全局最优焊接路径的较好近似解,并与改进的自适应遗传算法以及人工鱼群算法做了仿真对比试验.结果表明,人工蜂群算法不会过早停滞,具有较快收敛速度,较其它两种算法更能缩短焊接工时,基于人工蜂群算法的双机器人路径规划方法能有效解决搬运车车架主焊工序双机器人同步焊接问题. 相似文献
7.
8.
10.
11.
12.
13.
无芯模旋压由于不受芯模限制,适合复杂曲母线工件的柔性旋压成形,但仍需一定的辅助支撑,以克服成形形状精度较差的问题。针对主辅旋轮的曲母线件无芯模旋压,运用仿真与实验相结合的方法分析其在有无端部辅助支撑、有无辅助旋轮支撑时的旋压效果,分别对仿真结果的应力、应变、轮廓形状和壁厚分布情况进行了探讨。结果表明,端部辅助支撑有助于提高整体弯折变形效果,辅助旋轮支撑有助于板料局部成形,复合辅助支撑则综合了两者的成形特性,可以得到满足成形质量的工件。另外,通过变进给和首道次预成形直线形状的两道次旋压成形方法,对成形质量进行改善,结果表明两种方法相结合可以明显提高最大减薄率,改善壁厚均匀度。 相似文献
14.
Nowadays, sheet metal products are some of the most frequently found parts in industry. Progressive dies have a special role in various methods of sheet metal production. The design process however, requires a considerable amount of time and expertise. Two important activities during a progressive die design are “Nesting” and “Piloting”. In this paper, a software is introduced which automates the nesting of different parts according to minimum scrap strategy. The software is also capable of choosing the most suitable existing holes or designing auxiliary holes on the scrap part of the strip for piloting purposes. 相似文献
15.
R. Verma P. A. Friedman A. K. Ghosh C. Kim S. Kim 《Journal of Materials Engineering and Performance》1995,4(5):543-550
Superplastic forming characteristics of a fine-grained 5083 aluminum sheet have been investigated by means of gas-pressure
forming of a rectangular pan. This part geometry lends itself to a simple representation in terms of nearly one-dimensional
sheet stretching and permits reasonably rigorous control of strain rate throughout the forming cycle. This study followed
a study of the uniaxial tensile properties carried out on this alloy. A two-stage forming cycle, which comprised a short,
rapid prestraining stage followed by a stage of slower rate of superplastic straining, was used because the uniaxial tensile
work showed enhancement of superplastic response of this alloy under this condition. The study examined the effect of process
parameters such as initial gas pressurization rate, level of hydrostatic pressure, and lubricants on the thinning characteristics
of the sheet, especially along the die entry radii. The gas pressure/time cycle was suitably modified to avoid premature sheet
failure due to excessive sheet thinning or cavitation. Cavitation under the biaxial forming condition and the effect of hydrostatic
pressure on cavitation suppression were evaluated. A defect-free pan with sharp corners was formed. 相似文献
16.
G. F. Wang B. Wang S. S. Jang K. F. Zhang 《Journal of Materials Engineering and Performance》2012,21(10):2062-2066
The pulse current auxiliary thermal deep drawing (PCATDD) of SiCp/2024Al composite sheets with poor formability was investigated and an integrated high-efficient heating and deep drawing process design was developed to improve the formability of SiCp/2024Al composites. The average pulse current density was achieved at 21.7?A/mm2 with temperature of SiCp/2024Al composites reaching around 673?K in the 50?s. The temperature uniformity of the sheet electrified by the high-intensity pulse current and temperature gradients between the sliding core and top flat of female die were investigated to achieve precise temperature control of sheet and die. During electrification, the stainless steel inserts between the sheet and the copper electrodes successfully prevented heat dissipation and promoted temperature uniformity. Meanwhile, the temperature gradients can be efficiently controlled by blowing high-speed air. The workpiece showed good shape retention, surface quality, and high geometry accuracy. The present study has verified successfully the feasibility of process procedure for PCATDD of SiCp/2024Al composites sheet. 相似文献
17.
通过单向拉伸试验获得2B06铝合金原始O态和短时热处理板材的力学性能参数。采用有限元模拟方法模拟并验证了局部热处理差性板材在铝合金口框零件两次充液成形中的应用,分析了零件成形能力提高的机理。模拟结果表明:采用原始O态板材成形口框零件时,局部减薄严重,破裂危险区多发生在平面应变区域;合理的局部热处理方案使得板材具有软硬材料的梯度分布,显著提高了口框零件的成形能力。通过激光实验测温装置确定激光热处理的工艺参数,对涂有水基石墨热处理区域的板材进行热处理,使其成为差性板,再对差性板进行两次液压成形,验证了模拟的准确性。 相似文献
18.
本文介绍了微波炉钣金的自动化设备的组成,详细描述了自动线的线首、线中和线末的的组成和功能,期中线首主要由双工位上料机、拆垛机械手和定位台组成;线中主要由搬运机械手、冲压设备和模具组成,纤尾主要由收料皮带线组成,辅助设备主要由废料导料板和废料线组成,为钣金自动化生产提供了一种自动化生产的样板和思路,推动了制造业自动化智能化的发展。 相似文献
19.
钣金机匣作为航空发动机的主要构成零部件,其结构复杂、材料难于成形,且成形后内部存在不同程度的残余应力,随着计算机的发展,数值模拟成为辅助板料成形研究的主要手段,屈服准则是数值模拟的基础。本文对航空发动机机匣钣金成形性能做以叙述,对各向同性材料屈服准则、各向异性材料屈服准则、先进的各向异性材料屈服准则进行归纳,提出屈服准则应以屈服轨迹、单轴屈服应力、塑性各向异性参数等为选择依据,并提出未来屈服准则可沿新的屈服准则、描述非线性加载情况下的屈服轨迹、创新实验研究方法等方向发展。 相似文献
20.
利用共聚焦显微镜对冷轧薄板的色差表面形貌进行观察,发现条状色差主要是由于带钢表面粗糙度不均匀引起。通过生产现场调研发现,在焊缝连接处色差纹路具有连续性特征,且通过轧机急停取样后发现色差主要是由于连轧机的5#机架引起。分析表明,带钢粗糙度不均与轧制过程中乳化液油膜在工作辊面分布不均相关,而油膜不均与乳化液的喷射方式、轧制速度、乳化液的颗粒度和接触角存在直接关系。通过增加乳化液辅助喷嘴,控制轧制速度,并将轧制油的颗粒度由13μm降低至8μm,油滴接触角由80°降低至63°,色差缺陷得到解决。 相似文献