铝合金圆锥形零件粘性介质温成形研究

采用热力耦合有限元数值模拟方法对铝合金圆锥形零件粘性介质温成形过程进行了模拟分析,研究了成形过程粘性介质和板材的温度分布、不同温度条件下成形零件壁厚分布、成形载荷等.结果表明,圆锥形零件的底部圆角区域为成形危险区域.非等温粘性介质温成形过程中,在粘性介质内部形成的非均匀温度场影响了板材的温度分布.当粘性介质温度略低于板材温度时,坯料中心区域温度较低,有利于延迟底部圆角成形时的破裂,提高了零件壁厚的均匀性.分别进行了室温和加热时铝合金圆锥形零件粘性介质压力成形试验,试验结果与数值模拟具有相同的规律.     

板料应变视觉测量系统研究

介绍了板料应变视觉测量系统结构和基本原理。该系统运用立体视觉技术对板料成形物理模拟中的圆形坐标网格系统进行测量，获得变形板料的应变分布。实验结果表明，该系统可以较为迅速地完成各种成形工艺的板料件应变参数的测量与分析，并取得比较理想的精度。     

铝合金板温成形过程中凸凹模圆角处摩擦的测量

在温成形过程中铝合金板与模具表面的接触和摩擦行为十分复杂,不同的接触区域摩擦状况不尽相同。本文分析了板料成形中摩擦测量的国内外发展状况,采用自行设计的新型摩擦测量装置完成了铝合金板温成形过程中凸凹模圆角处摩擦系数的测量。该测量装置的特点是可以模拟板料的真实变形过程,因而可以获得更为准确的测量结果。     

基于ABAQUS的汽车板材成形性能及变形规律研究

在板料液压成形过程中,由于流体压力的施加,对板材的受力状态会产生不同程度的影响,同时可以在一定范围内有效提高板材的成形性能。为了分析流体压力下板材成形性能的变化规律,基于有限元软件模拟软件ABAQUS,对不同流体压力条件下的2024铝合金的单向拉伸过程分别进行数值模拟研究,得出了流体压力对板材米塞斯应力分布、轴向应力分布、伸长率及颈缩区厚度的影响规律。研究结果表明,在流体压力作用下,板材的变形更加均匀;并随着流体压力的增大,板材表现出更大的变形潜力,可以达到更大的伸长量。     

半球形件粘性压力成形的实验研究

本文对半球形件的粘性介质胀形进行了实验研究。充分利用实验设备的特点 ,分析了背压、介质排放口等粘性压力成形中的工艺参数对板材成形性能的影响。实验结果表明 ,粘性压力成形中背压及介质排放口分布的变化可以引起模腔中介质压力场的变化 ,在板材表面形成不同的压力分布 ,进而改变了板料的流动模式及应力状态 ,选取合适的背压及介质排放口的分布可以改善板材的成形性能     

板料成形三维全场应变摄影测量快速检测系统研究

针对目前板料成形过程中应变测量的实际问题,提出了一种新的测量方案,通过采用近景工业摄影测量与坐标网格分析法相结合的方法,可以高效地实现板料成形后表面全场应变的精确测量。基于以上方法设计并开发出了可以应用于实际的板料应变检测系统XJTUSM。通过对某些型号的钣金零件表面应变的测量,验证了本文方法的有效性。     

Combined experimental and numerical analysis of bulge test at high strain rates using split Hopkinson pressure bar apparatus

High strain rate bulge test technique which is introduced in this paper adopts a rubber-pad as pressure carrying medium to bulge a sheet metal at high velocity using split Hopkinson pressure bar (SHPB) system. The experimental set-up is based on conventional hydraulic bulge test which is modified to mount on SHPB. The thickness thinning of the sheet metal during the test will be considered as a measure of true strain of the bulged sheet. The theoretical approach is developed in this study to attain pressure–strain curves of sheet metals during high strain rate bulge forming process. This approach is followed by a finite element simulation of the process in ABAQUS/Explicit software. To verify the developed method, analytical and finite element methods are compared with experiments.     

平板毛坯电磁成形线圈的研究及应用

在电磁成形中,成形线圈是使电能变成磁场能,使毛坯产生塑性变形的关键部件.介绍了平板件电磁成形的基本原理,分析了线圈电感对电磁成形效率的影响,以及几种典型的平板线圈电磁力的分布特点和线圈失效的几种基本形式.指出在平板件电磁时,应根据所需成形力的大小和分布来选择和设计线圈,从而提高能量利用率,延长线圈的使用寿命.     

固体颗粒介质成形新工艺及变形研究

固体颗粒介质成形新工艺,是采用固体颗粒代替刚性凸模(或弹性体、液体)的作用,对金属板料成形的工艺。固体颗粒介质成形新工艺,即可以解决流体介质、粘性介质的密封难题,又具有内压非均匀分布、便于控制成形、提高材料成形极限、降低投资成本、所得零件表面质量高、成品率高的优点,且固体颗粒无工业污染,可重复使用。该工艺为材料的加工制备提供了新的方法和手段。利用塑性增量理论,对自由变形区任意一点的应变进行了分析,得到了自由变形区任一点的应变及厚度计算公式。采用固体颗粒介质成形工艺,进行板料成形试验,成功试制出多种典型工件;对试验件壁厚分布的计算值和实测值进行了比较,证明理论正确。     

Parametric analysis of warm forming of aluminum blanks with FEA and DOE

1 Introduction Warm forming of lightmass materials has been investigated as an alternative manufacturing process to achieve higher formability compared with forming at room temperature due to a substantial increase in material ductility[1?8]. SHEHATA et a…     

板料单点渐进成形中成形角对成形影响的模拟分析

介绍了金属板料单点渐进成形的基本原理;利用有限元软件LS_DYNA分析了板料渐进成形中当工具头压下时,不同成形角条件下,工具头与板料接触区域的应力分布;根据对模拟数据的分析比较,讨论了不同成形角对板料成形时的影响;就提高成形直壁件的高度提出了改进意见,并在试验中得到证实。     

不锈钢板料塑性成形摩擦机理的研究

介绍了不锈钢板料在塑性成形时的摩擦特点以及润滑剂在不锈钢材料和模具表面的成膜原理。对不锈钢板料在中、高接触压力下的滑动摩擦机理进行了试验研究，比较了使用不同润滑剂时，不锈钢板料塑性成形的摩擦状况。     

转轮叶片热模压成形压力中心的动态计算

为确保实际生产中压力中心的波动始终处于设定的公差范围之内,提出一种基于刚塑性有限单元法,通过实时节点力的计算来获取非均匀厚度板料成形压力中心的动态算法.推导了相应的计算列式,采用DEFORM软件二次开发实现了该算法.同时,建立了水轮机转轮叶片热模压成形过程的有限元模型,结合上述算法给出了具体的压力中心坐标值,为压力中心的优化提供了必要的数值基础.     

Deformation behavior of TC 1 titanium alloy sheet under double-sided pressure

In order to investigate the influence of normal stress through thickness on the formability of sheet metal, the viscous pressure bulge（VPB） tests of an annealed TC1 titanium alloy sheet were carried out under two different conditions： double-sided pressure bulging and conventional single-sided pressure bulging. The automated strain analysis, measurement environment （ASAME） and scanning electron microscope（SEM） were used to study the strain distributions and the fracture morphology of bulged specimens. It is found that thickness strain is increased for double-sided pressure bulging specimens, and the limiting dome height（LDH） of double-sided pressure bulging specimens is increased by 31.8% compared with conventional single-sided pressure bulging specimens. The dimples in fracture surface for double-sided pressure bulging specimens are larger and deeper than those for conventional single-sided pressure bulging specimens. The results indicate that normal stress through thickness is helpful in improving the formability of titanium alloy sheet metal.     

The non-hydrostatic response of polymer melts as a pressure medium in sheet metal forming

The polymer injection forming process is a recent invention for producing plastic?Cmetal hybrids. It is a combination of injection molding and sheet metal hydroforming process in which polymer melt serves as a pressure medium. This paper presents the experimental investigations on the non-Newtonian nature of thermoplastic melt as pressure medium. The objective of this work is to identify the presence of non-hydrostatic pressure distribution within the cavity and its influence on the final shape of the formed sheet metal component. Experiments are conducted with center-gated injection mold under varying processing conditions. The development of localized cavity pressure during the process is recorded and evaluated against the final shape of formed sheet metal. It has been observed that higher injection rate, higher injection temperature, and higher melt flow index of the processed polymer is necessary for the uniform pressure distribution and subsequently uniform forming of the sheet metal.     

EXPERIMENTAL RESEARCH AND NUMERICAL SIMULATION OF LASER SHOCK FORMING OF TA2 TITANIUM SHEET

Laser shock forming （ISF） was a new technique realized by applying an impulsive pressure generated by laser-induced shock wave on the surface of metal sheet. LSF of metal sheet was investigated with experiments and numerical simulation. The basic theories were introduced; the surface quality and deformation of the processed titanium sample （TA2） were examined; ABAQUS was used to simulate ISF and the central displacement of the shocked region was measured and compared with the simulation. Overlapped ISF treatment was experimentally carried out to produce groove and simulation. The results showed that the surface quality and the microstructure with single laser pulse had no remarkable change, and ablation was observed on the surface of the sample with overlapped pulses. The deformation observed in the numerical simulation agreeed with that observed in the experimental measurement quite well.     

基于厚板的三辊滚弯成形数值模拟及优化

滚弯成形由于结构简单、加工效率高而被广泛用于工业制造领域.首先,介绍了三辊滚弯技术的成形原理,借助几何模型对成形半径和上辊压下量之间的关系进行推导;然后,使用有限元分析软件ABAQUS对三辊滚弯成形的圆形截面工件进行数值模拟,从模拟结果分析了成形过程中的板材应力分布以及成形半径大小.鉴于板材加工过程中无法避免的回弹现象...     

拉深过程中压边力分布实验测量方法与数值模拟

通过数值模拟和实验,研究了压边圈结构对冲压成形过程中压边应力分布的影响,建立埋入式压边应力测量系统,对冲压过程中压边圈与板料之间的接触应力进行了测量,结果表明压边圈结构的变化对压边圈和板料之间的接触应力有显著影响,通过合理设计压边圈结构,可以实现在压边圈不同部位施加不同的压边应力,从而改善冲压件的成形性能.     

Numerical simulation of aluminum alloy ladder parts with viscous pressure forming

1　INTRODUCTIONTheeffectofstressstatesonaxisymmetricsheetformabilityhasbeenstudiedundertheconditionofsolidmetalpunchforming [14 ] ,andtheeffectofblankholderpressure (BHP) ,frictioncoefficientandpunchconfigurationonthestressstateshasbeenob tained .Becauseofthedisadvantagesofsolid punchforming ,newformingtechnologyisneededtoim provethestressstatesofthesheetinformingprocessandtomeettherequirementofforminglow plastici ty ,complexshapeparts .Viscouspressureforming(VPF)isarecentlydevelopedfle…     

大型船用卷板机卷板成形过程的数值模拟

首先对卷板成形过程进行了理论分析;然后用有限元分析软件ABAQUS对某大型船用卷板机板料滚弯成形及回弹的过程进行模拟,得到了成形件的应力分布与应变分布;研究了上辊不同下压量对其成形过程的影响,分析了滚弯过程中辊子和板料间的法向接触正压力,并将仿真值和理论计算值进行了比较,分析了产生误差的原因.同时,分析了辊子对板料的切...