共查询到20条相似文献,搜索用时 15 毫秒
1.
为了解决电磁管件胀形过程中磁场-结构场之间迭代耦合3D模拟的问题,采用ANSYS/EMAG得到不同时刻管件上的磁场力分布,并将节点力作为载荷输入到ANSYS/LS-DYNA进行管件动态塑性变形分析;然后将变形后的管件和空气网格输入到ANSYS/EMAG进行下一步的磁场分析。在管件变形过程中,对空气层网格采用任意拉格朗日算法,使空气网格能够随着管件的变形而有规则地变化,避免空气单元畸变。结果表明:管件外表面轴向中心点随时间位移值与实验结果基本一致;管件最终外表面轮廓与实验结果基本吻合;管件外表面轴向中心点位移与实验结果的误差为2.5%。 相似文献
2.
3.
文章将渐进成形的思想融入到传统的管件电磁胀形工艺中,提出管件电磁渐进成形的新工艺,即采用小尺寸线圈,通过移动多次成形的方式成形长管件。提出了适合于管件电磁渐进胀形工艺的顺序耦合数值模拟方法,并与一次放电、两次放电、三次放电的实验结果进行对比,模拟结果与3组实验数据均吻合。采用数值模拟的方法,进一步研究重叠率和成形顺序对管件变形均匀性的影响,研究结果表明,重叠率为50%、成形顺序为b→c→a时,可获得最佳的成形均匀性。电磁渐进成形技术应用于管件胀形工艺中具有可行性,对实际生产具有指导意义。 相似文献
4.
5.
6.
The effect of electromagnetic bulging on the fatigue behavior of the 5052 aluminum alloy was investigated through tensile–tensile fatigue testing. The intriguing finding is that the bulged specimens exhibited enhanced fatigue strength as depicted by maximum stress vs the number of cycles until failure (S–N) curves, by comparison with these original aluminum alloys. Although the fatigue process of the original and budged alloys follows the same mechanism with three distinct steps, namely, crack initiation at a corner of the tested samples, stable crack propagation with typical fatigue striations and finally catastrophic fracture with dimple fractographic features. The typical crack propagation rate vs stress intensity factor range (da/dN–ΔK) curves derived from the spacing of striations reveal a lower crack propagation rate in the bulged specimens. The enhancement of fatigue strength in electromagnetically bulged aluminum alloy is further rationalized in-depth on the basis of strain hardening and dislocation shielding effect. 相似文献
7.
8.
9.
三通管广泛应用于工业、建筑、装饰等行业,为了提高三通管的质量及降低加工成本,三通管胀形工艺研究势在必行.胀形工艺关键技术之一是胀形介质的选用,通过采用石蜡、粘土、尼龙、硅橡胶和聚氨酯橡胶等材料作为胀形介质进行了大量的胀形实验.从实验中得出的数据可知,以上各种介质都可以达到要求的胀形系数.但从得到零件的外部及内部的质量来看,并且结合金属流动规律分析得知,内壁要求高的工件,可选用尼龙、聚氨酯橡胶、硅橡胶为介质;反之,对内壁要求不高或无要求的工件,可用石蜡作为介质,并且可回收利用,降低成本.这对于三通管胀形技术的实际生产具有重要的指导意义. 相似文献
10.
in order to estimate the feasibility of electromagnetic casting (EMC) for different metals, a mathematical model named the electromagnetic dimensionless number (EMDN) was presented, and its validity was proved by the experiments of aluminum and Sn-3~Pb alloy. From the experiment and the analysis of EMDN it can be concluded that the EMC of steel can be attained only when the magnetic flux density is larger than 0. 09 T, while that required for aluminum is only 0. 04 T. The mathematical expression of the electromagnetic dimensionless number was given out. 相似文献
11.
磁脉冲自由胀形后的管件沿轴向材料分布不均匀,且由于其特殊的几何形状无法通过单向拉伸试验获取其材料参数。为获取磁脉冲胀形管的材料参数,提出了一种基于显微压痕试验的磁脉冲自由胀形管件材料参数的获取方法,整个材料参数获取过程包括显微压痕试验、显微压痕试验有限元模型的建立及验证和基于多岛遗传算法(MIGA)的计算反求3部分。通过显微压痕试验获取胀形管轴向不同位置点处的载荷-侵入量曲线,然后通过改变显微压痕有限元模型中的材料参数使仿真得到的载荷-侵入量曲线不断逼近试验的载荷-侵入量曲线,当两曲线在最小二乘意义上达到误差最小时,由仿真得到的材料参数即被认为是真实的材料参数。最后,将反求得到的不同位置点的材料参数整体代入到磁脉冲自由胀形管轴向压溃仿真中,通过比较轴向压溃仿真与轴向压溃试验的变形模式以及力-位移曲线、峰值力、平均力、总吸能等参数来验证参数的准确性。 相似文献
12.
对T2紫铜薄板进行电磁微胀形有模成形实验,研究不同电压及不同凹模深度对材料成形性能的影响。采用激光共聚焦显微镜及轮廓仪研究不同充电电压和不同凹模深度下的制件截面轮廓、成形深度的变化规律。研究结果表明:凹模深度一定,随着电压升高微通道成形精度不断提高,成形深度在7500V出现极值,随后制件表面逐渐出现反弹迹象,成形深度降低,表面质量下降;而当电压一定,随着凹模深度的减小,成形深度随之增加,微通道成形精度逐渐提高,在凹模深度为0.5mm时出现极值,随后精度逐渐降低,但随着凹模深度的降低制件表面的弹复现象逐渐减弱、排气不良留下的痕迹逐渐消失,表面质量不断提高。 相似文献
13.
14.
15.
The effects of the length of solenoid coil on tube compression in electromagnetic forming were investigated either by theory analysis or through sequential coupling numerical simulation. The details of the electromagnetic and the mechanical models in the simulation were described. The results show that the amplitude of coil current waveform and the current frequency decrease with the increase of the coil length. And the peak value of magnetic pressure is inversely proportional to the coil length. The distribution of the magnetic force acting on the tube is inhomogeneous while the tube is longer than the coil. The shortened coil length causes the increases of the maximum deformation and energy efficiency. The numerically calculated result and the experimental one of the final tube profile are in good agreement. 相似文献
16.
在电磁约束成形中通过Aψ-A三维有限元法所得的磁感应强度、涡流密度和集肤层厚度分布,求得电磁压力的分布;对具有不同宽厚比的带圆角矩形截面样件所受的电磁压力进行了分析.发现宽厚比越大的样件,相邻两边电磁压力之差也越大.圆角形状产生的涡流流向变化也能明显改变样件表面电磁压力的分布,当圆角半径接近或小于集肤层厚度时,角部与直边连接处形成一个电磁压力衰减区,这种电磁压力分布规律极大地增加了大宽厚比小的圆角矩形样件截面的成形难度. 相似文献
17.
Tendency of homogeneous radial deformation during electromagnetic compression of aluminium tube 总被引:1,自引:0,他引:1
Electromagnetic forming is one of the high-rate forming methods that can be extensively used to form and join axisymmetric metal sheet and tube. Tendency of homogeneous radial deformation during electromagnetic compression of aluminium tube was investigated through the design optimization method based on sequential coupling numerical simulation and experiments. The results show that the tendency depends on the length ratio of tube to coil (R), which has a critical value (Rc) corresponding to the relatively ... 相似文献
18.
利用ABAQUS有限元软件对2219铝合金环形件淬火过程及后续胀形过程中径向截面上残余应力的分布进行数值模拟,研究了胀形量对淬火残余应力消减率的影响。结果表明:淬火后环件的径向应力在上下端面呈压应力,在-106 MPa左右,在芯部应力值较小;周向应力和轴向应力均呈外部压应力、芯部拉应力的应力分布状态。胀形对环件的径向应力、周向应力和轴向应力均有显著的消减效果。胀形量在0.25%~4.00%范围内增加时,环形件的残余应力减小,周向应力和轴向应力的消减率都增大并趋于定值,且周向应力消减率的增大速度比轴向应力消减率的增大速度快。当胀形量<3%时,周向应力的消减率大于轴向应力的消减率,当胀形量>3%时,周向应力的消减率略小于轴向应力的消减率;当胀形量>2%时,周向应力和轴向应力的平均消减率>80%,环件的淬火残余应力得到很好的消减。 相似文献
19.
Effect of turbulent flow on electromagnetic elimination with high frequency magnetic field 总被引:1,自引:0,他引:1
1 Introduction The application of the electromagnetic body force to separate non-metallic inclusions was proposed by ALEMANY et al[1,2]. And ASAI et al have measured the migration velocity of polystyrene particles in a sodium chloride aqueous solution, in which a DC electric field and DC magnetic field were simultaneously imposed. They found that the direction of migration is opposite to the electromagnetic force and the migration velocity agrees well with the values calculated from the … 相似文献
20.
All-position welding is an important technology in energy sources, chemical, shipbuilding and other industries. When welding current is larger than 200 A, the molten metal tends to flow down due to the force of gravity. In order to "push" the molten metal into the weld, a new kind of U-frame excitation model, which could produce electromagnetic force to balance the gravity of the molten pool, was designed. The related parameters of the excitation model were simulated by Maxwell 3D, and the relationships between the parameters and the magnetic induction intensity were analyzed. Finally, the electromagnetic force in the molten pool was calculated, and the appropriate parameters of the U-frame excitation model were determined. The results of the simulation verify the feasibility of the all-position welding excitation model. 相似文献