后轮罩同步成形动态摩擦应用研究

结合后轮罩量产零件的模面逆向数据及生产工艺参数,研究恒定摩擦参数和动态摩擦参数下后轮罩的成形仿真分析结果与量产零件成形状态的一致性。通过分析研究成形极限图、板料流入量和减薄率数据发现,动态摩擦参数下的成形仿真结果更接近量产零件成形状态,后续的整车同步成形开发应将动态摩擦参数应用到薄板软钢深拉深及铝板拉深类零件的成形仿真分析中。     

盒形件无模充液拉深工艺参数研究

基于Dynaform平台对盒形件无模充液拉深工艺参数进行分析与研究,结果表明,合理地控制液体加载路径、预胀形压力以及成形时的液体压力可有效提高板料成形性能和成形件质量,通过与传统拉深工艺比较,无模充液拉深工艺在摩擦保持效应的作用下,拉深件壁厚更加均匀一致,盒形件一次拉深最大相对高度可达到4。     

非均匀变形件垫层拉深初探

分析了金属拉深变形时的摩擦状况,指出了拉深过程中材料流动的摩擦阻力主要是粘着点切断力和机械啮合力,提出了非均匀变形件拉深时在适当部位加上垫层可使拉深过程中的带动作用增强,使金属流动趋于均匀,从而提高拉成形极限。     

薄壁紫铜零件多次拉深成形的数值模拟

通过对薄壁紫铜筒形件在大拉深比时二次拉深成形方法的选择研究，由UG建立参数化模型，应用有限元软件Dynaform对拉深成形过程进行数值模拟，分析模具参数选取对成形性的影响和软件中若干参数的设置，得出紫铜薄壁高筒件的合适的拉深工艺和优化的工艺参数。     

工艺参数对方形盒拉深成形性能的影响

通过正交试验和Dynaform有限元模拟,研究了拉深工艺参数对方形盒成形性能的影响。正交试验设置了凸凹模间隙、凹模圆角半径及摩擦因子三个因素。通过方差分析和模拟可知:摩擦因子对成形力的影响最大;凸凹模间隙值对拉深高度的影响最大;凹模半径对壁厚的影响最大。结果表明:减小摩擦因子可以降低成形力;减小间隙值可大幅提高拉深高度;工艺参数对壁厚无明显影响。将优化的工艺参数应用到实际方形盒拉深成形中后,得到了合格的杯形件,验证了有限元模拟的正确性。     

板料拉深成形数值模拟摩擦模型及参数化实现研究

对板料拉深成形过程数值模拟新技术进行了研究，提出现有的摩擦模型的不足之处，拟提出一种全面考虑板料及模具的材质、表面粗糙度、接触应力、变形温度、变形程度、所用润滑剂的组分等情况的新摩擦模型，并拟用新摩擦模型来实现板料拉深成形过程数值模拟的的参数化研究。     

汽车油底壳一次拉深成形减薄率控制研究

运用Dynaform数值模拟软件,对汽车油底壳拉深成形过程中的拉深筋、压边力、毛坯形状、摩擦因数等多种工艺约束参数进行综合数值模拟,获得油底壳制件塑性成形的优化工艺方案。汽车油底壳最终拉深成形方案为不设置拉深筋,压边力取600 k N,摩擦因数取0.1,毛坯形状为圆弧化八角形,制件一次拉深成形后减薄、起皱、破裂等缺陷明显减少,生产的制件成形质量良好。     

镁合金AZ31B板材热拉深成形工艺研究

镁合金(AZ3lB)板材的成形性能可以通过热拉深试验来进行观察评估。成形温度选择在100-400℃之间。以获得适合成形的最佳温度范围。使用有限元方法分析了主要工艺参数对坯料成形质量的影响。试验结果表明。成形温度低于200℃时坯料很脆，高于400℃叶坯料表面易发生氧化而不适合成形。当成形温度选择在300一350℃之间。压边力在6-15kN(单位压边力q为0．7—1．7MPa)之间时镁合金具有较好的成形性能，能成功拉深出质量好的筒形件。数值模拟结果表明，坯料与模具间的摩擦因数对产生破裂的影响较压边力的影响程度大。     

轻型车前照灯反光镜拉深成形工艺及模具设计

轻型车前照灯反光镜是由抛物曲线构成的三维曲面深拉深件。在成形过程中容易产生起皱和拉裂现象。为解决这些缺陷，分析了反光镜拉深成形工艺及成形方法，在设计模具时重点考虑拉深筋参数的可变性，在理论计算的基础上，采用逐步增高拉深筋的试验方法，探讨了拉深筋参数对成形结果的影响，从而得到最佳的实际值。实际生产验证模具结构合理，拉深筋调整简单，模具调试周期短。     

轧制差厚板筒形件充液拉深成形影响因素的灰色关联分析

针对轧制差厚板零件在传统拉深成形工艺中易产生成形缺陷的问题，将充液拉深工艺引入轧制差厚板筒形件的成形中，并通过数值模拟技术对轧制差厚板充液拉深成形过程进行了研究。分析了液池压力对轧制差厚板成形性能的影响，并通过正交试验结合灰色理论讨论了不同工艺参数对轧制差厚板成形性能的影响规律。研究表明：充液拉深成形工艺相对于传统拉深成形工艺能够获取成形性能更好的轧制差厚板。随着液池压力的增加，轧制差厚板筒形件最大厚度减薄率呈现先减小后增大的趋势，而过渡区最大移动量逐渐减小，采用10 MPa的液池压力能够获取较小的最大厚度减薄率，并将过渡区最大移动量限制在较低水平。摩擦因数、压边力以及液池压力对于轧制差厚板充液拉深成形性能的影响程度是依次降低的，采用灰色关联分析获取的优化工艺参数组合可以提高轧制差厚板的成形性能。     

纯钼板材真空环境高温拉深性能研究

在25~870℃温度范围内进行了厚度为2.0 mm纯钼板的单向拉伸试验,建立了高温拉深有限元分析模型。通过数值模拟与试验对比分析,确定了纯钼板高温变形摩擦与温度的关系,研究了成形温度、润滑、压边间隙和模具尺寸对热拉深工艺的影响,并采用优化的工艺参数进行了平底杯形冲头热拉深试验。结果表明,润滑条件对纯钼板热拉深影响最显著,其次是成形温度;在成形温度870℃,拉深速度30 mm/min,有润滑,压边间隙2.5 mm的参数组合下,最大拉深比可达1.94。     

Thermal behavior of aluminum-coated 22MnB5 in hot stamping under dry and lubricated conditions

The hot stamping of aluminum-coated 22MnB5 has usually been conducted under dry condition, for which the forming load is high since the coefficient of friction is over 0.5. In order to decrease the forming load, the authors previously proposed the use of a lubricant to decrease so that the coefficient of friction from over 0.5 to 0.3. However, it is necessary to understand the heat transfer property in hot stamping under lubricated condition. The purpose of this paper is to examine the heat transfer property of aluminum-coated 22MnB5 in hot stamping under dry and lubricated conditions. In this study, the die and specimen temperatures were measured during compression and compression-sliding tests under dry and lubricated conditions using the hot flat drawing test simulator. In the compression test, the die and specimen temperatures measured under dry and lubricated conditions were the same. On the other hand, in the compression-sliding test up to a sliding distance of 70 mm, the die temperature under lubricated condition was lower than that under dry condition, and it was found that the heat transfer under lubricated condition is superior to that under dry condition. Consequently, there is a difference between the specimen temperatures under dry and lubricated conditions. However, from the results of the tensile test, there is no difference between the tensile strengths under dry and lubricated conditions.     

Investigation of Influencing Parameters for Tribological Conditions in Dry Forming Processes

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.     

工艺参数对TA0半球件冷拉深成形的影响规律

以TA0薄壁半球形零件冷拉深成形为研究对象,采用数值模拟与试验研究相结合的手段,在研究该拉伸成形过程中零件的应变及壁厚分布规律及组织演变规律的基础上,对破裂、起皱缺陷位置进行了预测。同时,采用正交试验分析方法,研究了单位压边力、摩擦系数、凹模圆角半径和凸凹模间隙等工艺参数,对该拉深成形过程的影响规律。结果表明,单位压边力、摩擦系数、凹模圆角半径对拉深过程均有显著影响,其中贡献率分别为凹模圆角半径41.04%,摩擦系数30.27%,压边力24.68%。     

方形盒制件圆角处拉深破裂的数值模拟

金属薄板成形的数值模拟技术在冲压件生产和模具设计中起着重要的作用。文章借助Dynaform软件对某方形盒制件拉深破裂现象进行数值模拟,分析其产生原因和影响因素,并利用正交实验找出防止该制件圆角破裂的拉深条件组合。结果表明,在冲压速度、凸模圆角半径、摩擦系数和板料厚度4个因素中,凸模圆角半径对盒形件拉深破裂的影响最大。为降低因圆角处板料剧烈减薄而产生破裂的几率,盒形件拉深时应采用较大的凸模圆角半径。     

Finite element analysis of sheet Hydromechanical forming of circular cup

Sheet hydroforming is a process of converting flat sheet into desired component geometry by using water pressure in a controlled manner. This paper dealt with sheet Hydromechanical forming (SHMF) of circular cup. In this process, blank is first placed on the lower die (a fluid chamber combined with draw ring) and then after sealing the blank between blank holder and draw ring, punch progresses to deform the blank. Pressure of the fluid chamber is also increased simultaneously with the punch progression. The present work endeavours to understand the effect of strain hardening exponent, anisotropy ratio and interfacial friction between blank and tools surfaces for different modes of deformation––stretching to drawing mode on sheet Hydromechanical forming of circular cups.A finite element (FE) model was developed for simulating the SHMF process using dynamic explicit, commercial code, LsDyna. The model after experimental validation used for studying the effect of above parameters on the process. The analysis reveals that higher cup depth with minimum thinning for forming dominated by stretching mode can be achieved with material of higher anisotropy ratio, strain hardening exponent by using a rough punch and effective lubrication at blank-die–blank holder interfaces. On the other hand in case of drawing as mode of deformation, thinning is influenced mainly by interfacial friction condition between blank and tool surfaces as compared to material properties.     

塑性成形过程摩擦测试的研究进展

摩擦是影响金属塑性成形及其过程有限元模拟的重要因素 ,因此有必要对其测试方法进行研究。本文介绍塑性成形过程摩擦测试研究方法和测试技术的研究现状与进展 ,并对模拟试验法和直接测量法各自的特点进行了分析。作者设计出一种新型的探针传感器 ,开发出了铝合金板料温成形过程摩擦在线检测系统 ,并对铝合金板(5 182 )圆筒形件温成形过程进行了摩擦测试。     

基于AutoForm的阶梯盒形件冲压工艺模拟及优化

阶梯盒形件是汽车制造业中的典型零件,但是由于其拉伸成形困难,废品率较高.针对某阶梯盒形件进行了工艺性分析,规划了冲压生产工艺,并利用AutoForm软件对拉伸成形过程进行了仿真模拟,选取板料尺寸、摩擦系数及压边力为研究对象,对比分析了3个参数对拉伸质量的影响规律,最后给出了优化成形质量的建议,对指导实际生产有一定的意义...     

板成形中摩擦系数测定的研究进展

本文阐述了摩擦系数在板成形中的作用及板成形中摩擦系数测定的国内外的发展状况 ,采用作者设计的新型摩擦系数测定装置进行了摩擦系数测定的实验研究 ,为进一步开展摩擦系数测定及摩擦边界的研究打下了基础 ,为有限元模拟的真实性提供了重要的参考依据。