基于Dynaform的某型钢圈轮辐成型过程仿真

以某型钢圈轮辐为研究对象,针对其实际成形过程中的起皱、拉裂缺陷,采用有限元仿真软件Dynaform对其成型过程进行了分析。结果表明,仿真分析不仅能为模具结构改进及成形工艺参数优化提供依据,而且可以大大缩短模具制造周期、降低生产成本,提高生产效率。     

基于液压成形的高强钢回弹分析研究

以大梁加强板为研究对象,基于Dynaform成形仿真软件对比液压成形与传统冲压成形对高强钢的回弹影响,并比较液压力、压边力对板料液压成形的回弹规律。结果表明:相比传统冲压成形,液压成形在截面1与截面2处最大回弹分别降低了46.1%与48.8%;液压成形工艺下,压边力与液压力的变化在零件不同截面及不同测量处的回弹规律不同。     

基于Dynaform的螺旋底外壳件液压拉深成形仿真技术研究

用Dynaform有限元仿真软件对汽车制动器螺旋底外壳件液压拉深成形过程进行了模拟,详细阐述了液压拉深成形仿真技术在制动器外壳件液压成形中的应用具体步骤,分析了压边力和液体压力对阶梯形件成形品质的影响。研究结果表明,合适的压边力和液体压力能防止制动器螺旋底外壳件拉深缺陷的发生。     

桥壳内高压成形工艺参数优化及试验研究

针对桥壳内高压成形过程的工艺参数优化进行了研究.根据桥壳零件结构的特点,确定了桥壳内高压成形的工艺过程;运用人工神经网络建模确定了工艺参数之间的关系,采用正交试验的方法分析了各项工艺参数对成形结果影响力的大小,并得到了最优工艺参数组合,即轴向位移进给量17 mm,进给时间0.1 s,液压加载峰值35.5 MPa,加载时间0.25 s.将优化后的工艺参数代入有限元模拟软件Dynaform得到数值解,验证了工艺参数优化结果的正确性,同时进行了内高压成形试验,零件轴向内高压成形的厚度值的仿真结果和试验结果误差为3.1％,径向结果误差为1.3％.试验结果与仿真结果吻合程度在合理范围内.     

制动器壳件液压成形建模仿真与模具数字设计

液压拉伸成形仿真与模具数字化设计能显著降低成本和提高制件质量,在设计制造领域中将广泛采用。研究了具有空间曲面特征的重载汽车螺旋底制动器壳件的Pro/E三维造型、Dynaform液压拉伸成形仿真建模技术和仿真成功后的模具Pro/E自动生成技术。研究结果表明,该零件底部通过数学公式建立扫描曲线,将Pro/E的实体造型和曲面造型功能两者巧妙地结合运用,成功地实现了有空间曲面特征的制动器壳件三维实体造型。再由此通过Pro/E和Dynaform各自的优势快速产生液压成形仿真的形面模型,实现了仿真快速建模,并设置合理参数进行仿真,成功后用Pro/E快速生成液压成形模具,实现设计-仿真数字化,为今后此类型的制动器外壳件液压成形生产提供了技术指导。     

基于Dynaform的可调式弯曲模结构设计与应用

针对柔性智能自动焊接生产线多规格、少批量产品需求,开发了可调式壳体弯曲模。利用有限元模拟分析软件Dynaform,对壳体弯曲模冲压工艺方案进行数值模拟分析,预测该产品的成形缺陷,根据成形CAE分析模拟结果,以产品回弹大小控制为目标,针对弯曲模拉伸深度、摩擦系数、拉伸速度等参数进行前期模拟分析。为后续智能自动焊接夹具固定提供保障。试模结果验证了Dynaform有限元成型分析的可行性,有效地评估模具的结构性能,同时采用合理冲压工艺可以缩短模具制造周期,保证柔性自动焊接生产线产品的生产质量。     

基于Dynaform的汽车翼子板的有限元分析

板料成型是利用金属板料在固态状态下的塑形,通过模具及外力作用而制成零件的一种加工方法。以板料成型的有限元软件Dynaform为平台,介绍了有限元分析流程,并对某种汽车翼子板冲压成型过程进行分析,包括压料面、工艺补充面、拉延筋等的设计,最终得到了成形极限图、应力分布图和材料减薄图,以这些数据为依据判断零件成形情况,这为优化工艺参数和模具结构设计提供了依据。     

基于Dynaform的微型轴承浪形保持架冲压成形工序仿真分析

针对微型轴承浪形保持架成形的不确定性,工件的内径检测困难,成形件的质量不易控制的问题,采用板料成形数值仿真软件Dynaform对浪形保持架的成形过程进行模拟仿真和优化,分析工艺参数和模具结构参数对成形件质量的影响,为浪形保持架加工工艺和质量控制提供一种新的方法。     

基于Dynaform的铝合金盒形件拉深过程研究

针对6061-T651铝合金盒形件拉深成形过程中存在的技术问题,应用Dynaform非线性有限元软件对盒形件的拉深过程进行模拟分析,得出压边力等工艺参数对拉深过程及成形质量的影响规律,确定了合理的工艺方案,并通过实验对方案进行验证,实验结果满足设计要求。     

基于DYNAFORM的一种零件连续翻边成形方法

金属板料的翻边成形是板料成形的重要组成部分,也是板料成形中的难点。重点研究折弯并向内的翻边结构,通常采用的成形工艺是先折弯成形后凸缘面翻边成形,通常产生的成形缺陷是凸缘部位产生起皱。利用Dynaform软件,以某企业的家用电器后壳为例,主要针对折弯并向内的翻边结构进行数值模拟,研究成型缺陷并确定合理的成形工艺,以改善成型结果。     

Analysis and design of hydroformed thin-walled tubes using enhanced one-step method

This paper deals with the analysis and design of tube hydroforming parameters in order to reduce defects which may occur at the end of the forming process, such as necking and wrinkling. We propose a specific methodology based on the coupling between an enhanced one-step method for the rapid simulation of tube hydroforming process and a surrogate model based on a metamodeling technique. The basic formulation of the one-step method has been modified and adapted for the modeling of 3D tube hydroforming problems in which the initial geometry is a circular tube expanded by internal pressure and submitted to axial feeding. In the surrogate model, approximate responses are built using moving least squares method and constructed within a moving region of interest which moves across a predefined discrete grid of authorized experimental designs. Two applications of tube hydroforming of aluminum alloy 6061-T6 have been utilized to validate our methodology. The final design is validated using experiments together with the classical explicit dynamic incremental approach using ABAQUS? commercial code.     

Multi-objective optimization and sensitivity analysis of tube hydroforming

Tube hydroforming is a manufacturing process used to produce structural components in cars and trucks, and the success of this process largely depends on the careful control of parameters such as internal pressure and end-feed force. The objective of this work was to establish a methodology, and demonstrate its effectiveness, to determine the optimal process parameters for a tube hydroformed in a die with a square cross section. The Taguchi method was used to establish a design of virtual hydroforming experiments, and numerical simulations were carried out with the finite element code LS-DYNA®. A sensitivity analysis was also carried out with analysis of variance. Multi-objective functions that consider necking/fracture, wrinkling, and thinning were formulated, and the response surface methodology was used with the most sensitive factors to obtain a defect-free part. An objective function, based on the final corner radius in the part, was also included in the optimization model. The forming severity of virtual hydroformed parts was evaluated using the forming limit stress diagram and the forming limit (strain) diagram. Finally, the normal-boundary intersection method and the L ₂ norm were used to obtain the Pareto-optimal solution set and the optimal solution within this set, respectively. The hydroforming process for this part was also optimized using the commercial optimization software LS-OPT®, with two different single-objective algorithms. However, the optimum load path predicted with the proposed methodology was shown to achieve a smaller corner radius. The proposed optimization technique helped to define a process window that leads to a robust manufacturing process and improved part quality.     

Development of automotive engine cradle by hydroforming process

The hydroforming technology may bring many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower springback, improved strength and durability and design flexibility. In this study, the whole process of front sub-frame parts development by tube hydroforming using steel material having tensile strength of 440 MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive engine cradle by the hydroforming process were carefully investigated. Overall possibility of hydroformable engine cradle parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydroforming. At the die design stage, all the components of prototyping tool are designed and interference with the press is examined from the point of deformed geometry and local thinning.     

Hydroforming of aluminum extrusion tubes for automotive applications. Part II: process window diagram

Based on the mathematical formulations for predicting forming limits induced by buckling, wrinkling and bursting of free-expansion tube hydroforming, a theoretical “Process Window Diagram” (PWD) is proposed and established in this paper. The theory developed in the first part of the present work was formulated within the context of free-expansion tube hydroforming with both combined internal pressure and end feeding. The PWD is designed to provide a quick assessment of part producibility for tube hydroforming. The predicted PWD is validated against experimental results conducted for 6260-T4 60×2×320 (mm) aluminum tubes. An optimal loading path is also proposed in the PWD with an attempt to define the ideal forming process for aluminum tube hydroforming. Parametric studies show that the PWD has a strong dependency on tube geometry, material property and process parameters. To the authors’ knowledge, this is the first attempt that a PWD is being formulated theoretically. Such a concept can be advantageous in deriving design solutions and determining optimal process parameters for tube hydroforming processes.     

A gradient-based decomposition approach to optimize pressure path and counterpunch action in Y-shaped tube hydroforming operations

In tube hydroforming, the concurrent actions of pressurized fluid and mechanical feeding allows obtaining tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. Main process parameters are material feeding history (i.e., the punches velocity history), internal pressure path during the process, and (in T- or Y-shaped tube hydroforming) counterpunch action. What is crucial, in such processes, is the proper design of operative parameters aimed to avoid defects (for instance underfilling or ductile fractures). Actually, the design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence and such issues can be pursued only if a proper control of process parameters is performed. In this paper, a design procedure for Y-shaped tube hydroforming operations was developed. The aim of the presented approach is to calibrate both internal pressure history during the process and counterpunch action in order to reach a sound final component. The approach utilized to optimize the aforementioned parameters is founded on gradient-based techniques and the optimization problem here addressed depends on a considerable number of design variables. In order to reduce the total number of numerical simulations/experiments necessary to reach the optimal values of the design variables, the basic idea of this paper is to develop a sort of decomposition approach aimed to take into account subsets of design variables in the most effective way. The proposed decomposition approach allows avoiding about 50% of the numerical simulations necessary to solve the same problem by traditional gradient technique.     

基于DASYLab的管材轴压胀形的加载控制

内压与轴向压力的合理匹配是管材轴压胀形成败的关键因素。本文利用数据采集与处理软件 DASYL ab实现了轴向压力基于内压的线性加载控制 ,为进一步研究更为复杂的管材轴压胀形的加载控制关系奠定了实验基础     

Analysis and finite element simulation of the tube bulge hydroforming process

To investigate the effect of the loading path on the forming result and get the reasonable range of the loading path in tube bulge hydroforming process, a mathematical model considering the forming tube as an ellipsoidal surface is proposed to examine the plastic deformation behavior of a thin-walled tube during the tube bulge hydroforming process in an open die, and thus different loading paths are gained based on this model. The finite element code Ls-Dyna is also used for simulating the tube bulge hydroforming process. The effect of the loading paths on the bulged shape and the wall thickness distribution of the tube are discussed, and then the reasonable range of the loading path for the tube bulge hydroforming process is determined.     

Analysis and finite element simulation of the tube bulge hydroforming process

To investigate the effect of the loading path on the forming result and get the reasonable range of the loading path in tube bulge hydroforming process, a mathematical model considering the forming tube as an ellipsoidal surface is proposed to examine the plastic deformation behavior of a thin-walled tube during the tube bulge hydroforming process in an open die, and thus different loading paths are gained based on this model. The finite element code Ls-Dyna is also used for simulating the tube bulge hydroforming process. The effect of the loading paths on the bulged shape and the wall thickness distribution of the tube are discussed, and then the reasonable range of the loading path for the tube bulge hydroforming process is determined.     

Optimization of loading path in hydroforming T-shape using fuzzy control algorithm

The loading path is crucial to the quality of forming parts in the process of tube hydroforming, and thus the design and optimization of loading path is an important issue for tube hydroforming. Wrinkling is a catastrophic defect for thin-walled tube hydroforming. In order to avoid wrinkling, an adaptive simulation approach integrated with a fuzzy control algorithm is used to optimize the loading path of hydroforming a T-shaped tube. The tubular material used is stainless steel and has an outer diameter of 103 mm and the wall thickness of 1.5 mm. The controlled variables are the axial feeding, the counterpunch displacement, and the internal pressure. A code is developed to make the optimization automatically, which works together with LS-DYNA. Six evaluation functions are adopted for identifying geometrical shape and quality of T-shape. Failure indicators obtained from the simulation results are used as the input of the fuzzy control, and then process parameters are adjusted according to the expert experiences in the fuzzy controller. In this way, a reasonable loading path for producing a sound T-shape is obtained, and also a T-shaped product is successfully hydroformed by experiment. The result shows that the fuzzy control algorithm can provide an adequately reliable loading path for hydroforming T-shaped tubes.     

Study on the crushing and hydroforming processes of tubes in a trapezoid-sectional die

A study on the bulging processes of tubes in a trapezoid-sectional die has been carried out through finite-element (FE) analysis. A FE model of the single-step hydroforming process and several FE models of crushing combined with subsequent hydroforming processes in a trapezoid-sectional die with different die closing seams are proposed. The simulations are performed using the FE code LS-DYNA. For the single-step hydroforming process, the effects of loading paths on the formability of the trapezoid-sectional part are investigated. In the case of the crushing combined with subsequent hydroforming processes, the effects of die closing seams, tube diameters, and preforming loading paths on the forming process and the final parts are analyzed. A comparison between the parts formed through single-step hydroforming process and through crushing combined with subsequent hydroforming processes is performed. Finally, an experiment of tube hydroforming in a trapezoid-sectional die is carried out on the hydroforming machine developed by Shanghai Jiaotong University. The simulation results show good agreement with the experimental results.