FE analysis on Deformation and Temperature Nonuniformity in Forming of AISI-5140 Triple Valve by Multi-Way Loading

In triple valve forming process by multi-way loading severely nonuniform deformation and temperature distributions are prone to occur, which may lead to poor forming quality and macro-micro defects. A 3D coupled thermo-mechanical rigid-viscoplastic finite element (FE) model for multi-way loading forming of AISI-5140 steel equal diameter triple valve was developed based on DEFORM-3D. Through comprehensive simulation and analysis, the influences of main process parameters on the forming process and nonuniformity of deformation and temperature were studied. The results showed that: (1) the degree of deformation nonuniformity decreased with the increase of the punch loading speed, initial temperature of billet, or the decrease of the friction factor; (2) the average temperature of forming body increased as the punch loading speed, initial temperature of billet and the friction increased, while the degree of temperature nonuniformity decreased with the increase of punch loading speed or decrease of initial billet temperature.     

Ti-15-3钛合金橡皮成形的摩擦因数(英文)

用网格应变自动测量分析系统测量Ti-15-3钛合金板料刚模胀形试验的极限应变,并进行拟合以获取Ti-15-3钛合金的成形极限图。通过分析刚模胀形、橡皮胀形、液压胀形等试验的"拉拉"区极限应变,可知橡皮胀形的极限应变最大,接近等双拉时的,橡皮硬度对胀形极限应变的影响很小。用平板摩擦试验初步确定Ti-15-3钛合金与刚模间无润滑无变形条件下的摩擦因数。将试验与有限元模拟结合,分别分析Ti-15-3钛合金刚模胀形及橡皮胀形的应变,确定润滑条件下双拉变形时的Ti-15-3板料刚模间的摩擦因数以及Ti-15-3板料橡皮间的摩擦因数。Ti-15-3板料刚模间的摩擦对成形影响很大,而Ti-15-3板料橡皮间的摩擦对成形的影响则很小。     

深冲用电镀钢板的摩擦特性及表面损伤的研究

采用扳成形动卷摩擦因数测试装置对两种铡扳(热浸镀 电镀,即GA-E钢板;IF钢电镀锌钢扳,即EG钢板）以及未电镀的裸板进行摩擦特性研究,着重研究了成形模具温度对摩擦的影响,并对两种镀层钢板经拉深后的表面损伤进行了分析。研究结果表明：(1)在相同的变形条件下,与EG钢板相比,GA-E钢板的摩擦因数随温度增加的变化幅度较小;(2)两种镀层钢板的摩擦因数均随冲头速度的增加而降低;(3)GA-E钢板接触表面损伤的主要形式为微裂纹,而EG钢板的接触表面损伤为犁划痕。     

基于MSC.SuperForm的金属体积成形数值模拟摩擦模型的二次开发

针对金属体积成形数值模拟,在反正切摩擦模型基础上,建立了考虑温度、压力和变形程度等的多因素摩擦模型,可以充分地考虑体积成形过程中速度、温度、单位压力和变形程度对变形体与模具之间界面的影响.采用该多因素摩擦模型对体积成形软件MSC.SuperForm进行了二次开发,通过实际算例分析,并与已有的文献结果对比,说明了提出的多因素摩擦模型的合理性.     

锂离子电池电芯铝塑膜外壳冲压成形工艺

通过正交试验,应用有限元仿真,对影响锂离子电池铝塑膜外壳冲压成形质量的各工艺参数的显著性进行分析,得出凸模圆角半径与凹模摩擦系数的选择对铝塑膜冲压工艺质量影响较大。利用数值模拟以及BP神经网络与遗传算法极值寻优,对锂离子电池铝塑膜的冲压成形工艺参数(凸模圆角半径、冲压速度、凹模摩擦系数以及压边力)进行优化。优化后的工艺参数使得锂离子电池铝塑膜的最大减薄率减少10%。实验证明,成形铝塑膜外壳的边角位置减薄最为严重,是影响成形铝塑膜外壳整体质量的关键性因素,可以作为衡量锂离子电池铝塑膜外壳成形质量检验的标准。     

滑动轴承冲压成形的有限元数值模拟

以滑动轴承的冲压成形为研究对象,利用ANSYS／LS-DYNA软件显式算法,实现滑动轴承扩口翻边的整个模拟过程。影响滑动轴承冲压成形的主要因素有凸模锥角、摩擦系数和冲压力。通过对这些因素进行Taguchi正交实验设计,分析各因素对冲压过程中应力应变的不同程度的影响。研究表明,合适的凸模锥角和压力对滑动轴承冲压成形具有很大的影响作用。研究结果对滑动轴承的成形工艺制定和模具结构设计具有一定的指导作用。     

Numerical simulation and analysis on the deep drawing of LPG bottles

Deep drawing is one of the most used sheet metal forming processes in the production of automotive components, LPG bottles and household goods, among others. The formability of a blank depends on the process parameters such as blank holder force, lubrication, punch and die radii, die-punch clearance, in addition to material properties and thickness of the sheet metal. This paper presents a numerical study made on the deep drawing of LPG bottles. In particular, the application of both variable blank holder forces and contact friction conditions at specific location during deep drawing are considered. The numerical simulations were carried out with DD3IMP FE code. A variable blank holder force strategy was applied and the numerical results were compared with results from other blank holder force schemes. It is evident that the proposed variable blank holder force scheme reduces the blank thinning when compared to other schemes; the friction coefficient also has a significant influence on the stress–strain distribution.     

5083铝合金弯头冷推弯数值模拟及试验研究

为成形高质量的5083铝合金弯头管件,采用有限元数值模拟方法对冷推弯过程进行了工艺模拟,模拟过程中研究了推制速度以及摩擦系数对成形质量的影响规律,并根据模拟结果对弯头进行了实际冷成形制备研究.结果表明,推制速度为4 mm·s-1、摩擦系数为0.06是优化的成形工艺参数.实际冷成形结果与模拟结果较为吻合.研究表明,控制推...     

Practical determination of friction coefficient of Al 3003 for forming of backward extruded part using simple tip test and inverse finite element analysis

The friction coefficient for aluminum alloy 3003 was determined from a specially designed tip test and finite element (FE) simulations. Measured radial tip distance after the tip test was compared to the FE simulations by iteratively changing friction coefficient and the best fitting friction coefficient was determined. To consider strain rate effect on flow stress response during large plastic deformation, a new combined Hollomon- Voce hardening law was proposed. The friction under three different surface conditions was considered by the proposed inverse FE analysis. The results showed that there was obvious strain rate effect on the predicted punch load in the tip test. Moreover, the different friction coefficients were numerically determined for punch/workpiece and die/workpiece interfaces. Two possible causes of this difference were discussed by the analysis on contact normal pressure and slip velocity distributions of the two interfaces.     

基于有限元法的三通管接头多向模锻成形仿真与优化

针对三通管接头在模锻成形中易出现破裂、材料折叠、冲头载荷大等问题,研究了冲头速度、坯料初始温度、摩擦系数对锻件模锻质量的影响.通过Deform软件,研究了水平冲头和垂直冲头等速进给、水平冲头和垂直冲头差速进给、水平冲头进给而垂直冲头不运动3种工艺条件下锻件的成形规律,并基于上述最佳工艺,研究了坯料初始温度对模锻过程中温...     

蛋盒型结构成形过程数值模拟研究

蛋盒型结构是一种轻质、高强、具有吸能特性的新型结构,其成形过程和最终成形形貌对性能有很大影响。首先描述了蛋盒型结构的成形过程及受力情况;随后运用Abaqus/Explicit软件对典型蛋盒型结构的成形过程进行了模拟,得到了成形极限高度时的形貌、减薄率、成形力等;最后分别分析了凸模结构参数、摩擦系数对蛋壳型结构成形结果的影响规律。研究表明:凸模半径的增加会增大成形力及成形极限高度,摩擦系数的作用会使最大减薄位置由凸模顶点位置向外移动;当选用凸模半径为周期间距的1/5时,摩擦系数在0.1~0.15之间时成形效率较高。     

Tribological Size Effects in Sheet Metal Forming Measured by a Strip Drawing Test

The aim of this work is to identify the tribological size effects within sheet metal forming and to develop a size-dependent friction function for the integration in the FEM-simulation. A strip drawing test with deflection in combination with a numerical identification is used. The numerical identification is based on an analytical model for the punch force and an optimisation program, which identifies the friction coefficient in dependence on the contact pressure from the measured punch force vs. punch travel. Scaled experiments with sheet thicknesses from 0.02 mm to 2 mm were done to identify the tribological size effects.     

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.     

金属管接头复合成形过程有限元模拟及实验研究

针对凸筋类金属管接头提出了一种新的管接头复合成形工艺：“缩口－轴压－胀形”复合成形工艺,分析了该复合成形的工艺特点,利用刚塑性有限元方法对复合成形过程进行了模拟,得出了不同时刻的网格变形图和等效应变的等值线分布图,讨论了缩口半锥角和摩擦因子对成形极限的影响,将刚塑性有限元计算的结果与实验结果进行了比较,并得出了一些对生产实际有价值的结论     

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.     

奥氏体不锈钢变薄拉深过程的数值模拟

利用有限元软件Deform-2D,对奥氏体不锈钢变薄拉深过程进行热力耦合的数值模拟,研究了凸、凹模与坯料间摩擦和变形速度对变薄拉深过程的成形载荷和坯料损伤的影响。模拟结果显示：当凹模与坯料之间的摩擦增大,成形载荷和坯料损伤明显增大;当变形速度增大,坯料损伤增大而成形载荷减小。上述结论为奥氏体不锈钢变薄拉深工艺优化设计提供了可靠的理论依据。     

轿车非典型U形件冲压成形工艺及模拟研究

利用板料成形模拟软件Dynaform对某轿车非典型U形件的冲压成形过程进行模拟,研究凸、凹模间隙、凸模速度、摩擦因数等对板料成形后厚度的影响,经多次模拟及对模拟结果进行分析,确定可行的成形工艺参数,用于指导实际生产。     

Experimental and numerical investigation on micro deep drawing process of stainless steel 304 foil using flexible tools

Flexible forming technology provides significant application potential in various areas of manufacturing, particularly at a miniaturized level. Simplicity, versatility of process and feasibility of prototyping makes forming techniques by using flexible tools suitable for micro sheet metal forming. This paper reports the results of FE simulation and experimental research on micro deep drawing processes of stainless steel 304 sheets utilising a flexible die. The study presents a novel technique in which an initial gap (positive or negative) is adopted between an adjustment ring and a blank holder employed in the developed forming system. The blank holder is moveable part and supported by a particular spring that provides the required holding force. The forming parameters (anisotropy of SS 304 material, initial gap, friction conditions at various contact interfaces and initial sheet thickness) related with the forming process are in details investigated. The FE models are built using the commercial code Abaqus/Standard. The numerical predictions reveal the capability of the proposed technique on producing micro metallic cups with high quality and large aspect ratio. To verify these results, number of micro deep drawing experiments is conducted using a special set up developed for this purpose. As providing a fundamental understanding is required for the commercial development of this novel forming technique, hence the optimization of the initial gap in accordance with each sheet thickness, thickness distribution and punch force/stroke relationship are detected.     

基于DeForm的密封条钢带滚压成形过程有限元分析

以某汽车密封条钢带骨架为研究对象,利用DeForm有限元分析技术对密封条钢带骨架滚压成形过程建立有限元仿真模型,根据模型分析滚轮基本直径递增量和摩擦系数变化对成形过程中带料等效应力和应变的影响规律。结果表明适当增大滚轮基本直径的递增量和减小滚轮与带料之间的摩擦系数,可降低带料成形过程中的等效应力和应变,有利于保证密封条钢带骨架成形过程稳定并防止产生边缘波浪、褶皱等缺陷。