板式翅片滚压成形过程仿真

采用一种新型滚压工艺进行板式翅片加工,简述了板式翅片的成形原理及滚压刀具的设计原则;利用DEFORM-3D软件对其成形过程进行模拟仿真,获得了理想的模拟翅片结构;分析了成形过程中工件的应力应变状态和滚压刀具在成形中的受力状况,通过加工实验验证了该方法的可行性。     

板式翅片滚压成形过程仿真

采用一种新型滚压工艺进行板式翅片加工,简述了板式翅片的成形原理及滚压刀具的设计原则;利用DEFORM-3D软件对其成形过程进行模拟仿真,获得了理想的模拟翅片结构;分析了成形过程中工件的应力应变状态和滚压刀具在成形中的受力状况,通过加工实验验证了该方法的可行性。
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矩形平顶翅片散热带成型过程数值模拟与试验分析

矩形平顶翅片散热带目前在加工过程中多采用仿形刀具连续滚压再经后续修整达到所要求形状尺寸的方法进行成型,存在成本高效率低、翅片成型质量不稳定等问题,通过使用有限元分析软件DFORM-3D对该成型过程进行数值模拟并结合模拟结果与试验数据进行比较,验证了结果的一致性,缩短了设计周期,降低了制造成本,为矩形平顶翅片散热带成型刀具快速准确研发提供了经验。     

波纹形翅片成形过程的有限元模拟与分析

为了提高波纹形翅片成形刀具的设计成功率与效率,通过显式动力学软件ANSYS/LS-DYNA对翅片的成形过程进行了有限元模拟,仿真结果与实际加工结果吻合。分析了刀具的参数、装配误差及刀具与铝片间的摩擦因数对翅片成形尺寸的影响规律。发现刀具的重合度不宜过大,否则会导致翅片的成形尺寸误差过大和翅片的外形发生畸形。刀具的中心距装配误差除了影响成形翅片的长度尺寸外,还会影响翅片顶弧长度与斜边长度的比例。刀具与铝片间的摩擦因数大小同样影响翅片成形尺寸。     

翅片在切削-挤压成形过程中的应力分析

对翅片在切削-挤压成形过程中的力学特性及变形机理进行研究。提出了翅片在切削-挤压成形过程中的力学模型，利用ANSYS有限元软件计算了翅片内部的应力分布状况，对容易产生断裂和裂纹的位置进行了预测和分析，给出了进给量、切削深度和刀具主偏角对翅片应力分布的影响规律。分析结果与实验结果基本一致。     

工艺参数对外翅片管成形过程影响的研究

采用无屑滚压—犁切复合成形工艺加工三维外翅片管。对翅片的成形过程和加工的特点进行了研究,并建立了翅片尺寸的预测模型;通过切削实验,获得了进给量、主偏角、切削深度等工艺参数对翅片高度和间距的影响规律。经理论预测和实验研究,对切削用量参数和刀具几何参数的合理选择进行了分析。     

基于DEFORM-3D的花键成形分析

基于刚塑性有限元法基本理论,并借助于通用三维有限元分析软件DEFORM-3D建立了花键冷滚压成形全过程三维动态有限元模型,对花键冷滚压成形过程进行了有限元模拟分析。揭示了花键冷滚压成形过程的等效应力、等效应变的分布情况和金属流动规律,从而为花键冷滚压成形工艺研究提供理论依据。     

成形辊齿数对蜂窝半格结构件成形影响研究

高强度金属蜂窝芯的制备方法是将金属箔材滚压成为蜂窝半格结构件,然后将其胶结或点焊成为蜂窝芯。基于蜂窝半格结构件滚压成形的工艺特点,利用ANSYS/LS-DYNA有限元软件对蜂窝半格结构件滚压成形进行有限元建模及弹塑性分析,得到了箔材成形过程中成形辊齿数对成形件形状尺寸、应力应变的影响规律。将有限元弹塑性分析结果应用于成形辊设计及制造,并将成形件的仿真数值与实验数值进行比较。结果表明:运用有限元分析来解决传统箔材滚压成形的缺陷是有效的。     

基于ANSYS的铝制错列锯齿翅片成形回弹研究

以铝制错列锯齿翅片为研究对象,利用ANSYS/LS-DYNA非线性动力有限元求解功能,模拟了翅片成形过程与卸载后回弹变形的全过程,得到了成形过程中任意时刻各处的应力、应变和卸载后板料的回弹结果。研究翅片成形过程中压边力、板料厚度、冲压速度、刀具齿形组合、刀具圆角半径等对回弹的影响。利用回弹规律进行模具补偿设计,以此优化专用翅片成形机及模具的结构参数和工艺参数,从根本上提高铝制错列锯齿翅片的制造精度,为翅片的结构优化设计提供了可靠的依据。     

基于ANSYS渐开线花键冷搓成形全过程的数值模拟

依据大变形弹塑性有限元理论和接触理论，综合考虑成形中的几何非线性、状态非线性、材料非线性以及工件与刀具的接触摩擦因素，借助有限元软件ANSYS对渐开线花键冷搓成形的过程进行数值模拟，方法新颖独特，其应用将对刀具的设计有参考作用。     

轴承套圈冷辗加工过程有限元模拟分析

运用大型通用有限元程序 ,建立轴承套圈冷辗加工的力学模型 ,采用非线性Lagrange大变形有限元方法 ,对工件金属的弹塑性变形过程进行模拟分析。通过工件工作区的应力分布云图考察金属材料的塑性流动情况 ,分析冷辗成形的机理。观察模型加载后不同时间应力分布云图的变化 ,并对比不同尺寸的辗辊、以及大小不同的载荷对工件加工变形过程的影响。分析冷辗加工中经常出现的轴承套圈失圆等异常情况形成的原因     

The use of dual-stream functions in the analysis of three-dimensional metal forming processes

Modelling metal forming processes with the dual stream function technique is considered. The dual stream function concept is reviewed. Its numerical implementation in a computer program is presented. The method enables the numerical evaluation of the process power and gives detailed information about other process parameters such as friction between the workpiece and the tool, workpiece geometry and material characteristics. Two selected examples concerning three-dimensional flat rolling and polygonal forging are analysed by this technique. The theoretical predictions are compared with results obtained by other authors using alternative methods. Computational advantages over other methods, namely the finite element method are the main feature of the present analysis.     

工艺参数对多楔轧件接口质量的影响规律

楔横轧多楔成形工艺是生产长轴类零件的先进方法,但生产过程中模具工艺参数对轧件接口质量的影响比较复杂。根据楔横轧多楔模具的工艺特点,建立多楔轧制长轴类零件的三维有限元模型。基于ANSYS/LS-DYNA有限元模拟软件,在不同模具工艺参数下对多楔轧制过程进行了有限元模拟,得到模具工艺参数对轧件接口质量的影响规律。在与模拟工艺参数相同的条件下进行轧制试验,试验结果和模拟结果一致。通过对理论模拟和轧制试验获得结果的分析,得到工艺参数中过渡角对轧件的接口质量影响最大、展宽角对轧件接口质量影响最小的结论。综合考虑各工艺参数的影响,给出保证轧件接口质量良好的过渡角选择范围。研究结果为多楔成形长轴类零件的模具设计提供理论依据和参考。     

Influence of cooling condition of tools on central deformation of workpiece and tool wear in cross wedge rolling

In this paper, a thermal–mechanical coupled simulation model for two-roll cross wedge rolling (CWR) was developed to investigate the influence of cooling condition of tools on central deformation of workpiece and tool wear by using three-dimensional rigid-plastic finite element method. Based on the simulation results, the information about central deformation of workpiece and tool wear with and without tool cooling was compared and analyzed. The study results indicate that forging quality and tool life can be improved by means of cooling the tools with cooling water. Subsequently, an industrial example of CWR in blank forming for engine connecting rod was presented to verify the feasibility of study results. In this industrial application, higher forging quality and longer tool life were obtained, which benefits the decrease of production cost. This study provides insights into the mechanisms of central deformation of workpiece and tool wear under different cooling conditions of tools in CWR process as well.     

Analytical modeling and numerical simulation for three-roll bending forming of sheet metal

The three-roll bending forming of sheet metal is an important and flexible manufacturing process due to simple configuration. It is suitable for forming large sheet parts with complex, curved faces. Most researches on roll bending forming of large workpiece are mainly based on experiments and explain the process through macroscopic metal deformation. An analytical model and ABAQUS finite element model (FEM) are proposed in this paper for investigating the three-roll bending forming process. A reasonably accurate relationship between the downward inner roller displacement and the desired springback radius (unloaded curvature radius) of the bent plate is yielded by both analytical and finite element approaches, which all agree well with experiments. Then, the three-roll bending forming process of a semi-circle-shaped workpiece with 3,105 mm (length)?×?714 mm (width)?×?545 mm (height) is simulated with FEM established by the optimum tool and process parameters. Manifested by the experiment for three-roll bending forming of this workpiece, the numerical simulation method proposed yields satisfactory performance in tool and process parameters optimization and workpiece forming. It can be taken as a valuable mathematical tool used for three-roll bending forming of large area sheet metal.     

基于数控车床为平台的柔性滚压研究

描述了一种对回转类零件进行滚压的工艺方法，将滚压工具施压于工件表面产生变形，滚压压力可通过弹簧进行调节，滚压产生的变形能提高工件表面的光滑度和硬度。不同的压力和轴向进给速度可滚压出不同的粗糙度和硬度。     

Study on multiple-step incremental air-bending forming of sheet metal with springback model and FEM simulation

A mathematical model of springback radius was developed with dimensional analysis and orthogonal test. With this model, the punch radius could be solved for forming high-precision semiellipse-shaped workpieces. With the punch radius and other geometrical parameters of a tool, a 2D ABAQUS finite-element model (FEM) was established. Then, the forming process of sheet metal multiple-step incremental air bending was simulated with the FEM. The result showed that average errors of the simulated workpiece were +0.68/?0.65 mm, and provided the process data consisting of sheet feed rate, punch displacement and springback angle in each step. A semiellipse-shaped workpiece, whose average errors are +0.68/?0.69 mm, was made with the simulation data. These results indicate that the punch design method is feasible with the mathematical model, and the means of FEM simulation is effective. It can be taken as a new approach for sheet metal multiple-step incremental air-bending forming and tool design.     

Surface characterisation in forming processes by functional 3D parameters

Tribology in metal forming plays a significant role for process feasibility and process quality. Especially in micro forming the influence of the tribological condition is very essential due to an extensive increase in friction which is observed while scaling processes from macro to micro. As friction depends considerably on the surface topography of tool and workpiece, functional surface characterisation concerning the tribological properties becomes even more relevant. Standardised 2D roughness-measurements and -parameters are notable to fulfil this task satisfactorily. Hence the surface has to be measured three dimensionally. An appropriate method is given by confocal white light microscopy. New 3D parameters are defined with respect to the functional behaviour of the surface. These parameters are derived from a mechanical-rheological model which describes the transmission of the forming load from the tool to the workpiece. In order to calculate these parameters, the software WinSAM has been developed. Especially the maximum closed void area ratio and the volume of closed lubricant pockets have already proven their capability of characterising the tribological behaviour of the surfaces in the macro world. It is expected that these parameters are a basis for a functional characterisation of the topography in micro-forming applications as well.     

Analysis of a cross wedge rolling process for producing drive shafts

The paper discusses the problems of forming parts such as stepped shafts by cross wedge rolling (CWR). In industrial practice, this rolling process is performed at stages, i.e., in several passes, when large cross-sectional reductions are involved. The same can also be done using a different design of this forming process, namely, multi-wedge cross rolling (MWCR), in which the workpiece is simultaneously formed by several pairs of tools (wedges). This paper compares the above two methods with respect to forming a drive shaft. Wedge tools used in both forming processes are described, and the numerical results of the simulations performed to verify the adopted solutions are reported. The results demonstrate that the MWCR method offers more advantages than the classical CWR technique. Consequently, MWCR is then verified in experimental tests. The experimental results confirm that parts such as stepped shafts can be formed by the MWCR method.