喇叭形灯罩拉深成形有限元分析与正交优化

分析了影响喇叭形灯罩成形性能的主要因素:压边力、凸模圆角半径、板料厚度和冲压速度。借助Dynaform软件对喇叭形灯罩拉深成形进行了单因素分析,得到了合理的压边力、凸模圆角半径、板料厚度和冲压速度的取值范围。采用正交试验方法对以上因素进行了多因素的正交优化分析,得到了最优的参数组合。     

电机并头套成形工艺参数研究与模具结构优化

通过数值模拟分析与正交试验相结合研究了成形工艺参数对矩形电机并头套弯曲后回弹的影响,确定了最优工艺参数组合。并进行了试验,验证了模拟结果,采用模具补偿法进一步减小回弹。结果表明:凸模圆角对回弹影响最大,其次是模具间隙,而凹模圆角与冲压速度对回弹的影响很小;回弹量随凸模圆角半径的增大而增大,随模具间隙的增大而增大,随凹模圆角半径的增大而先减小后不变,随冲压速度的增大呈现出先减小后增大的趋势;使用最优工艺参数的模具进行了成形试验,验证了模拟的正确性;设计的模具补偿法可进一步减小回弹。     

板材冲压成形摩擦系数实时测量系统设计研究

为了准确的反映板材成形过程中摩擦系数的真实情况,构建板材冲压成形摩擦系数实时测量系统,通过改变凸模圆角半径、凸模拱高和模面曲率半径、拉深筋圆角半径等几何参数,利用有限元软件计算不同模具模面下板材冲压及胀形过程中材料流动的变化情况,得到了材料流动量随各种参数变化的规律曲线,并以此优化设计了板材拉深及胀形模具模面,确定了组合式特征传感器的安装位置,为板材成形摩擦系数实时测量平台的建立提供了指导依据.     

轨道车辆侧柱成形缺陷数值分析

主要研究了轨道车辆车体钢结构中侧立柱构件的冲压成形工艺,对截面回弹的主要影响因素压边力、凸模圆角半径、凸、凹模间隙等进行了数值分析和优化,并加以实验验证。实验结果表明,成形件截面回弹量得到有效控制,解决了截面开口量过大问题,获得了高质量成形件。     

镁合金AZ31盒形件拉深成形有限元模拟分析

摘 要:利用有限元数值模拟分析了各工艺参数(拉深温度、凸模圆角半径及凹模内圆角半径)对镁合金AZ31盒形件拉深成形性能的影响,并通过实验进行了验证.结果表明:采用最佳拉深温度和最佳的凸模圆角半径、凹模内圆角半径可以有效地改善厚度为0.5mm的镁合金AZ31板材的拉深成形性能.     

连续矩形盒壁板的冲压成形试验与模拟研究

降低连续矩形盒壁板的减薄率对提高冲压深度和结构效率具有十分重要的意义。采用具有代表意义的5A06-O态铝合金双排六矩形盒壁板进行冲压成形试验,并使用有限元软件ABAQUS模拟成形过程,通过二者结果的对比,分析了壁板各区域材料流动特征。针对模具圆角半径和凸模底部润滑提出了降低该类壁板减薄率的结构设计要求与工艺润滑措施。结果表明:采用根据有限元模拟结果设计的凸凹模圆角半径,且凸模底部为零摩擦时,壁板成形效果最好。将本文的有限元分析方法与结论运用于实际产品的工艺与模具设计,取得了良好效果。     

汽车刹车盘冲压成形工艺分析

分析了QH142汽车前刹车盘的冲压成形工艺,采用了美国ETA公司的DYNAFORM软件进行拉伸变形过程的数值模拟,根据模拟结果确定出较为合理的毛坯形状和圆角半径;改进了翻边凹模刃口的形状,确保了翻边高度一致;将冲定位孔的凸模做成锥形凸模,提高了孔径的精度;多孔冲压时凸模采用阶梯形布置,减少了冲裁力;采用数控技术加工冲压异形孔的凸、凹模,提高了冲压件的质量,满足了尺寸精度要求。     

不锈钢管的拉伸外翻成形研究

以Dynaform5.6为平台,采用有限元数值模拟的方法对不锈钢管拉伸外翻成形过程进行了研究.研究表明,利用拉伸模可以实现不锈钢管的外翻成形,且通过改变拉伸凸模的圆角半径可获得不同间隙值的双层管;管端法兰宽度和压边力对不锈钢管的拉伸外翻成形力的影响很小,但不能忽视它们对外翻变形的影响;凸模的圆角半径对成形力的影响很大,凸模圆角半径取2 mm时稳态成形力约为最小,当凸模圆角半径大于或小于2 mm时,稳态成形力都会增大.     

基于Dynaform的L形件弯曲回弹有限元分析

以L形件为研究对象,根据板料成形特点及回弹规律,利用Dynaform软件对L形件冲压成形进行了回弹仿真试验。依据回弹仿真试验结果,用正交试验法对冲压参数凸凹模圆角半径、板材厚度、压边力和摩擦系数与L形件冲压回弹之间的关系进行了分析。结果显示,凸凹模圆角半径、板材厚度、摩擦系数对L形件的冲压回弹有显著影响。当弯曲工艺参数处于合理范围内时,L形冲压件回弹量随凸凹模圆角半径增大而增大;随板料厚度的增大而越小;随摩擦系数和压边力的增大,回弹角先增后减。     

DP590高强度板拉深成形应变路径规律研究

以某盒形件为例,以有限元分析软件Dynaform为平台,建立DP590高强度板拉深成形有限元模型,研究凸模圆角半径及摩擦系数对拉深成形应变路径的影响.结果表明:适当增大圆角尺寸可有效提高成形性能,增大摩擦系数减小材料流动,不利于高强度板的成形.     

Experimental Investigations of Bend Force in Air Bending of Electrogalvanized Steel Sheets

This article deals with bend force behavior of electro-galvanized (EG) steel sheets in air bending process. A detailed experimental study was carried out on EG steel sheets of various coating thicknesses to investigate the influence of parameters such as coating thickness, orientation of the sheet, punch radius, die opening, die radius, and punch velocity on bend force behavior. From the results, it is found that zinc coating reduces the bend force and the increase in coating thickness reduces the bend force significantly. It is observed that the bend force is larger for larger punch radius, smaller die opening, and smaller die radius. It is also observed that the bend force is larger for 0° orientation than for 90° orientation. The bend force decreases with increase in punch velocity, and this influence is more prevailing in EG sheets than in plain sheets.     

Improvement of stretch flangeability of ultra high strength steel sheet by smoothing of sheared edge

Stretch flangeability of an ultra high strength steel sheet having small ductility was increased by improving quality of a sheared edge. The effect of the quality of the sheared edge on the stretch flangeability of the high strength steel sheets was examined from expansion of a sheared hole with a conical punch. The quality of the sheared edge varied with the clearance between the punch and die, and the quality influenced the limiting expansion ratio. It was shown from measurement of surface of the sheared edge that the limiting expansion ratio of the sheared ultra high strength steel sheet is dependent on the macroscopic unevenness and hardness of the sheared edge and not on the microscopic roughness. The macroscopic unevenness of the sheared edge was eliminated by smoothing the edge with a conical punch. It was found that the smoothing of the sheared edge is effective in improving the stretch flangeability of the ultra high strength steel sheet.     

Computer aided engineering of the sheet bending process

The effects of the punch nose radius and sheet thickness on the elastic springback and residual stresses in the 90° V-punch and U-die bending process of AA 5083 aluminium alloy have been extensively studied by numerical simulations based on the finite element method. The results show that, irrespective of the sheet thickness and punch stroke, the springback ratio is not affected by the punch nose radius. Such results are in excellent agreement with the experimental ones obtained in similar conditions. As far as punch nose radius effects on the residual stresses are considered, significant differences were observed between residual stresses predicted with different nose radii. In particular, the shifting of the neutral layer and increase in the magnitude of the residual stresses predicted by the FEM code were found with decreasing punch nose radius.     

高强度钢板V形弯曲板厚方向压缩对回弹的影响

定量评价了V形弯曲凸模在到达下死点后在板厚方向的压缩作用对减小回弹的影响.利用弹塑性有限元法对高强度钢板V形件的弯曲成形和回弹过程进行模拟,并通过实验进行验证.模拟结果显示:回弹随平均压强与抗拉强度比值的增大而减小;凸模圆角半径对回弹的影响不大;有限元网格划分影响回弹的模拟结果,细分网格并在与凸模接触的部分增加单元数量...     

800MPa级DP钢冲压成形及裂纹扩展机理

通过冲压弯曲试验研究800MPa级DP钢的极限拉伸,采用扫描电子显微镜观察分析钢板的微观组织及动态拉伸过程,探讨其微观组织与其稳机理的关系。结果表明,DP800钢断口为剪切型断裂。凸模圆角半径较小时,拉深弯曲断裂是由于折弯角过小而在凸模圆角处折弯断裂;凸模圆角半径较大时,冲压弯曲断裂由于受到板料延伸率的限制,在材料流动受限的凹模圆角附近断裂。DP800的断口均分布着大量韧窝的韧性断裂,其裂纹扩展机理是微裂纹,主要产生于铁素体或马氏体/铁素体相界面,主裂纹沿两相界面或贯穿铁素体而继续扩展。     

Springback characteristics of steel sheets for warm U-draw bending

The purpose of this study is to investigate the characteristics of springback for various process conditions of the U-draw bending operation. The process variables are the forming temperature and the tool geometry, including punch profile radius (Rp) and die profile radius (Rd). In order to control springback, the use of a warm forming method is applied. For the warm draw-bending, five steps of temperature ranges, from room temperature to 200°C, were adopted. Two kinds of steel sheets, cold rolled carbon steel (SCP1, for general purposes in the automobile industries) and TRIP (transformation-induced plasticity) steel, were adopted. TRIP steel was the newly developed high-strength steel sheet. The results indicated that elevated temperature and the geometry of tools in the two kinds of steel sheet affected the springback.     

工艺参数对热镀锌钢板拉深成形性能的影响

充分发挥计算机数值模拟与物理实验相结合进行研究的优点，运用正交分析方法，针对影响热镀锌钢板拉深成形性能的主要工艺参数(凹模圆角半径、凸模圆角半径、压边力以及润滑剂)进行正交试验，得出以上4种工艺参数对热镀锌钢板成形性能影响的显著性指标，并对工艺参数进行了优化组合。     

The effect of die materials on the strain distribution in electro-galvanized sheet steel forming

The punch load and strain distribution of two deformed sheet steels, aluminum killed drawing quality steel (AKDQ Bare) and electro-galvanized drawing quality steel (AKDQ E.G.), are examined under the various process conditions including, die materials, punch speed, blank holding force, drawbead height and lubricant. The punch load and strain distribution ot Bare sheet steel forming is higher than that of E.G.sheet steel on the Kirkesite die set and are reversed on the GM 241 die set. The punch load and strain distribution on the Kirkesite die set is lower than those of the GM 241 die set. The changes of punch load and strain distribution ot the deformed cup for two sheet steels are affected by the frictional behavior of each sheet steel. It shows that the changes of frictional behavior having to be considered in the die design.     

拉形动态摩擦系数的正交试验分析

用正交设计法对拉形时的摩擦系数进行了测定,方差分析结果表明,平整量越大摩擦系数越小;润滑剂对摩擦系数的影响最大;摩擦系数随凸模行程的增大而增大,且基本为线性关系。凸模圆角半径处的摩擦系数比凹模圆角半径处的摩擦系数普遍大,这是由凸模圆角半径处的板材变形程度大、板材表面粗糙化大所引起。     

Slight clearance punching of ultra-high strength steel sheets using punch having small round edge

A slight clearance punching process of ultra-high strength steel sheets using a punch having a small round edge was developed to improve the quality of the sheared edge. No crack from the edge of the punch was generated by relaxing concentration of deformation with the punch having a small round edge, and the fracture was delayed. A small edge radius of 0.13 mm was effective for improving the quality of the sheared edge of ultra-high strength steel sheets, the increase in shiny burnished surface. The delayed fracture was prevented by the increase in compressive residual stress for the punch having the small round edge. For 1000 strike punching of an ultra-high strength steel sheet having a tensile strength of 1200 MPa, a sheared edge of high quality was produced with a TiAlN-coated punch having the small round edge. In addition, the chipping of the punch edge was prevented even for a slight clearance by the small round edge. It was found that both small round edge and slight clearance are indispensable for high quality punching of ultra-high strength steel sheets having low ductility.