薄板深拉深压边力变化规律研究

压边力(BHF)是薄板拉深成形过程中的一个重要工艺参数,本文应用能量理论分析法建立了应变强度εi的计算模型,该模型比传统模型更接近于实际,且基于εi建立的压边力模型在成形极限允许范围内能有效地抑制起皱,对提高拉深件质量有着重要意义。     

板料拉深成形过程中的变压边力技术

压边力是板料成形过程中的重要参数之一。在概述压边力在生产中的主要用途和意义的基础上，从压边力的加载模式、理论模型、实验研究变压边力技术与拉延筋、人工智能技术的交叉应用等方面，比较全面的综述了压边力技术的研究现状及存在问题，并探讨压边力技术的研究方向。     

A theoretical,numerical, and experimental investigation of plastic wrinkling of circular two-layer sheet metal in the deep drawing

In this paper, the wrinkling of two-layer (aluminum-stainless steel) sheets in the deep drawing process, is investigated through an analytical method, numerical simulations, and experiments. In a deep drawing process, wrinkling can always be eliminated with an increase in the blank holder force (BHF). Thus, the aim of this study is to obtain the minimum required BHF to prevent wrinkling. In the analytical model, energy method is used to predict the wrinkling. Also, FE simulations were performed to study the effect of forming parameters on wrinkling. Experiments have been conducted to verify the analytical model and FE simulations. The effects of parameters such as the material properties of aluminum layer and lay-up on BHF and forming force are investigated. Results demonstrate that the optimum BHF is dependent on the blank geometry, material properties and lay-up. It is shown that BHF is greater when aluminum is in contact with the punch. Results show a good agreement between analytical, FE, and experimental results.     

变压边力拉深工艺的研究

压边力是板料成形过程中的重要参数之一.本文在概述压边力在生产中的主要用途和意义的基础上,从压边力的加载模式、理论模型、实验研究变压边力技术等方面,比较全面的综述了压边力技术的研究现状,并探讨了压边力技术的研究方向.     

变压边力拉深工艺的研究

压边力是板料成形过程中的重要参数之一。本文在概述压边力在生产中的主要用途和意义的基础上,从压边力的加载模式、理论模型、实验研究变压边力技术等方面,比较全面的综述了压边力技术的研究现状,并探讨了压边力技术的研究方向。     

数值模拟波动压边力对拉深件成形质量的影响

钣金成形拉深工艺中,压边力的数值大小和方向是一个重要的工艺参数,在拉深过程中,对压边力大小和方向的控制,往往决定了拉深件的成形质量。然而,现有对变压边力的研究较多集中于线性且稳定的加载。从压边力波动变化的角度分析波动压边力对拉深件成形质量的影响,并考虑不同波形对这一影响有何变化,提出了一种更为有效的提高拉深件成形质量的方法。     

基于板料冲压的压边力拉深成形数值模拟分析

压边力是板料拉延成形过程的重要工艺参数之一,合理控制压边力的大小,可避免成形件起皱或破裂等缺陷.建立了三角冲压件的有限元模型,利用DYNAFORM软件,采用数值模拟的方法研究了三角形冲压件拉深时,压边力随时间及位置变化对成形性能的影响.分析结果表明,通过控制拉深过程压边力值的大小和分布,能有效地控制金属的流动,提高板材的成形性能.     

铝合金车门防撞梁热冲压成形缺陷(英文)

通过试验和数值仿真研究生产车门防撞梁中经常出现的减薄、破裂、起皱和回弹成形等缺陷。建立了适用于350~500°C的本构模型,并用于铝合金热冲压数值仿真。进行冲压试验和数值模拟以弄清成形缺陷的量化规律并分析工艺参数对成形缺陷的影响。研究结果表明:铝合金热冲压中破裂现象得到改善,回弹基本消除。增大压边力可减轻起皱的程度,但压边力超过15 kN将导致工件最大拉深处破裂。在压边力为3~5 kN,冲压速度为50~200 mm/s及有润滑的条件下,可以避免成形缺陷的产生。     

A Comparative Study on Formability of the Third-Generation Automotive Medium-Mn Steel and 22MnB5 Steel

Third-generation advanced automotive medium-Mn steel, which can replace 22MnB5 steel, was newly developed to improve the lightweight and crashworthiness of automobile. Studies on the formability and simulation method of medium-Mn steel have just been initiated. In this study, finite element simulation models of square-cup deep drawing were established based on various material property experiments and validated by experiments. The effects of blank holder force (BHF), fillet radii of tools (die and punch) on the maximum drawing depth (MDD), thickness distribution of the formed products, and the microstructure before and after forming were investigated and compared with those on 22MnB5 steel. Results show that the MDD of the two steels decreased with increased BHF but increased with the fillet radius of punch; however, the fillet radius of die showed no significant effect on the MDD for both steels. Compared with hot-formed 22MnB5 steel, the martensitic transformation of the hot-formed medium-Mn steel is rarely influenced by the process parameters; thus, it holds the complete, fine-grained, and uniform martensitic microstructure. Moreover, the medium-Mn has better formability, lower initial blank temperature, and smaller impact of BHF and fillet radius of tools on the hot-formed product. Thus, a theoretical basis for the replacement of 22MnB5 steel by medium-Mn steel in hot forming process is provided.     

利用正交试验设计优化冷弯成形工艺参数

冷弯成形工艺参数的设计对冷弯成形产品质量有重要影响。本文对方矩形管冷弯成形过程中机架间距、摩擦因数和轧制速度的不同取值水平通过正交试验设计,利用Abaqus有限元软件的显式非线性动态分析对所设计试验仿真模拟,得到了每道次轧制过程中带钢边部最大纵向应变最小时各个道次3个工艺参数的最佳取值。并用优化后的参数进行仿真和验证,得到各道次带钢边部最大纵向应变比优化前要小,优化后第4~第10道次带钢纵向应变极值相对接近,产品边部拉伸小,并且边部拉伸分布比较均匀,有效改善了产品质量。     

汽车铝板顶盖成形回弹优化的数值模拟研究

针对汽车铝板顶盖在冲压成形过程中容易出现回弹等问题,以某车型汽车铝板顶盖为例,采用Autoform软件对其冲压成形过程进行了仿真模拟,对比了采用不同拉深工艺零件成形结果。通过优化零件天窗区域的翻边工艺,零件成形回弹得到了控制。     

STUDY ON THE FINITE ELEMENT NUMERICAL SIMULATION OF SHEET METAL FORMING

Based on the Finite Element Theory of Rigid Plastic, relevant problems during plastic simulation on sheet metal forming were technologically studied and simplified; a simplified model of the blank holder during the drawing process was established and the effects of related parameters on the forming processes were also studied. At the same time, a finite-element numerical simulation program SPID was developed. The distribution of strain and relationship of stress-stroke simulated were compared with experimented, the results are well coincided with each other. It is verified that the analytical program is reliable.     

基于状态空间法的板料成形过程闭环控制系统的建模及仿真

冲压过程中,因材料的性能参数、润滑条件的波动和模具参数的改变,导致冲压件质量的不稳定,因此必须提高冲压件质量的控制鲁棒性。压边力是板料冲压过程的重要工艺参数之一,合理控制压边力的大小,可以避免起皱或破裂等缺陷。文章提出了一种基于结合RBF神经网络和经典状态空间理论的板料成形过程控制策略,并建立了其控制模型。引入时序分析法,将压边力的调整与反映工件成形质量的法兰边的吸入量误差联系起来,同时应用非线性最小二乘法识别出增益系数。仿真结果表明,在加入一噪声后,仍能获得满意的冲压件质量,模型具有较高的控制鲁棒性。     

盒形件拉深过程中的变压边力影响研究

拉裂和起皱是板材拉深过程中的主要失效方式,研究表明,合理的压边力能有效降低拉深失效的可能性.本文通过数值模拟的方法把变压边力的压边方式应用到拉深过程,并和实际情况相比较,发现合理的变压边力能改善板材的成形性能.     

差厚拼焊板汽车覆盖件回弹的研究

以差厚拼焊板覆盖件中通道为研究对象,根据零件结构图分析其工艺性。利用Dynaform软件对中通道进行冲压成形模拟,并设置前处理相应的一些工艺参数,得到初步模拟结果。然后对初步结果进行工艺参数优化和回弹模拟,分析拉延筋布置、压边力和板厚比对拼焊板回弹的影响。研究结果表明,拉延筋高度为4 mm、压边力为700 kN、板厚比为0．5时,回弹量为1．839 mm (小于回弹量经验值2 mm),符合生产要求。最后将模拟回弹量与实际生产现场进行对比,发现上顶面回弹量最接近实际数据,而侧壁和法兰部分回弹量和实际数据差别明显。     

Adaptive FEM simulation for prediction of variable blank holder force in conical cup drawing

Fracture and wrinkling are two primary failure modes in deep drawing of sheet metal parts. Previous studies showed that properly selected variable blank holder force (BHF) profile, i.e. variation of BHF with punch stroke, can eliminate these failures to draw deeper parts. In this study, an adaptive simulation strategy was developed to adjust the magnitude of the BHF continuously during the simulation process. Thus, a BHF profile is predicted in a single process simulation run and the computation time is reduced. The proposed strategy has been applied successfully to two conical cup drawing operations. The predictions have been compared with experiments and the results indicate that the adaptive simulation strategy can also be used to improve the drawing process for forming non-symmetric parts.     

基于响应面法的汽车发电机磁极锻造成形工艺多目标优化

针对汽车发电机磁极锻造成形过程中出现的填充不满、成形载荷过大、局部应力过大等缺陷,采用Deform软件对磁极锻造成形过程进行数值模拟分析。以降低未填充率、成形载荷和局部应力最大值为优化目标,以坯料直径、锻件温度、挤压速度和摩擦条件为优化变量,通过4因素5水平的中心复合试验,采用响应面法进行建模分析,最终得到3个优化目标的二阶响应面模型;对所建立的模型进行方差分析,通过模拟试验验证了该模型的准确性和可靠性。实际生产表明:采用优化工艺参数组合可以得到成形缺陷较小的磁极锻件,锻件成形精度可以达到±0.5 mm;成形载荷和局部应力最大值得到降低;提高了模具寿命及生产效率。     

新型变压边力拉深模设计

针对板料拉深成形过程中压边力控制较难的问题,根据凸轮机构运动的特点,设计了一种由曲柄滑块机构和凸轮机构组成的拉深模变压边力机构,该机构在拉深模工作过程中,能够合理控制压边力的大小。实践表明,变压边力拉深模满足拉深工艺要求,改善了拉深产品质量。     

汽车轮毂轴管复合挤压成形数值模拟与试验研究

根据热挤压成形理论,针对汽车轮毂轴管零件自身的特点,采用复合挤压成形工艺进行热成形,借助DE-FORM-3D有限元软件对成形过程进行了模拟、分析。以镦挤成形工序和反挤压成形工序为重点,分析了成形过程中金属的流动规律及应力、应变的分布情况,得到载荷-行程曲线。同时在试验时研究了加热温度、挤压速度、润滑等主要工艺参数对金属流动、应力应变、成形质量和成形力的影响。并以此为依据,对工艺参数进行了优化,验证了数值模拟结果的正确性及该复合挤压成形工艺的可行性。     

铝合金半球形件冲压成形数值模拟与实验研究

变形铝合金冲压成形性能研究是国内外研究的重点课题。本文以铝合金半球形件为例,采用实验和数值模拟相结合的方法探索了铝合金半球形件冲压成形的基本规律。研究表明,压边力对铝合金板材件的冲压成形质量具有重大影响,合理的压边力能大大提高铝合金半球形件的成形性。另外,采用仿真软件对板材件的冲压成形过程进行模拟分析,可大大缩短产品及模具的开发周期,提高产品的成形质量及市场竞争力。