材料参数对汽车发动机隔热板冲压成型性能影响

本文利用拉伸试验获得的样本数据,通过冲压性能试验和膨胀性实验,分析汽车用铝合金板材料参数和其成形性之间的对应关系,建立了评估铝合金板胀性成形性和拉深性的指标,为发动机隔热板冲压成形合理选材和预测成形性提供可靠的依据,为其它铝制品零件冲压加工中合理选材和预测成形性提供参考性的依据。     

燃料电池金属双极板精密成形技术研究和发展

首先对国内外关于金属双极板的材料选择进行了概述,然后对已有的各种精密成形工艺的选材、生产原理和特点进行了详细介绍,在此基础上提出了塑性成形作为一种生产效率高、零件机械力学性能好的生产工艺是金属双极板成形技术将来的发展方向。     

前围外板的冲压工艺设计及成形分析

目的解决汽车覆盖件因为冲压变形复杂,成形工艺参数难以确定的问题。方法分析了汽车前围外板的成形工艺,研究了复杂型面拉深模具的型面设计,以有限元分析软件AUTOFORM为平台,对其冲压成形过程进行了数值模拟。根据模拟结果(成形极限图、材料流动分布及材料变薄率)对拉延型面及工艺参数进行了优化。结果所得零件材料最大减薄率为17.3%,在SPCE(t=0.8 mm)材质减薄率安全范围内(18.7%),消除了成形过程中的暗伤开裂风险,成形结果得到了大大改善。结论 CAE仿真能够预测零件成形过程中存在的缺陷,优化工艺参数,指导模具设计工作。将优化结果用于指导实际生产,得到了符合质量要求的拉延零件。     

隧道防水板的施工质量控制

本文从防水板的选材、铺设前的准备工作、铺设工艺及注意事项、质量检查方法和缺陷修复方面,详细阐述了隧道防水板的施工质量控制方法与措施,值得推广运用。     

汽车立柱加强板成形分析

目的轻量化是汽车零部件设计的发展方向,汽车立柱因需要在碰撞中承受外力而变形,并为其他零件提供足够强度和刚度的安装点,一般都使用高强钢材料制造,以达到轻量化的要求。方法对采用DP590高强钢制造的典型结构汽车B柱加强板进行了工艺分析,以提出高强钢立柱加强板零件的设计及成形工艺优化方案。通过AutoForm软件的板料仿真技术,对采用590DP高强钢的典型汽车B柱加强板的冲压工艺进行了数值模拟分析。结果成功预测了板料成形过程中可能存在的起皱、开裂等问题。结论分析结果为汽车立柱加强板冲压工艺提出了改进方案,实现了模具的设计及优化。     

轻量化拼焊板构件塑性成形研究进展

拼焊板构件因容易实现轻量化、低成本、短周期成形制造而被广泛应用于飞机、汽车工业中,但在这类构件的塑性成形中,焊缝引入的材料、几何、边界条件非线性显著增加了成形复杂性,导致成形质量及成形极限下降,尤其是在具有强烈不均匀变形特征的弯曲、旋压等局部加载塑性成形中表现得更加明显,极大制约了轻量化拼焊板构件的精确塑性成形。为此,国内外学者在拼焊板构件弯曲及旋压变形机理与成形规律方面开展了大量研究。从焊接材料不均匀力学行为表征、拼焊板构件弯曲及旋压成形有限元建模、焊缝特征对变形行为影响及工艺设计等方面综述了相关研究进展,最后提出了拼焊板构件塑性成形仍面临的关键难题与挑战,对认识和发展轻量化拼焊板构件塑性成形具有重要指导意义和参考价值。     

汽车防撞梁外板冲压工艺设计

目的研究汽车防撞梁外板的冲压成形工艺,解决汽车覆盖件拉延成形过程中,在工艺补充面设计、压边力和拉延筋的布置时存在不确定性的问题。方法以汽车覆盖件防撞梁外板为例,基于曲面造型和有限元模拟软件,对其冲压成形过程进行了设计、模拟和优化。结果在优化工艺参数和合理改善零件结构后,获得了较理想的成形效果,为实际工艺设计和试模生产提供参考依据。结论提出一种优化新思路:利用冲压工艺多工序相结合的特点,合理调整零件内部结构,可以有效降低拉延成形工序的制造难度,从而提高制件质量。     

5系铝合金车门内板冲压成形及回弹研究

目的 在整体式车门内板上应用质量较轻的5系铝合金材质以达到新能源汽车的轻量化要求。方法 在工艺设计阶段,采用AutoForm数值分析软件及CAE数值仿真分析技术预测零件的成形难点及回弹趋势;分析整体式车门内板的深度,并提出几种改善零件成形性的方案;根据回弹结果对模具型面进行回弹补偿;对模具加工、调试等重要环节进行深度管控。结果 成功解决了零件9个区域的成形问题。对已量产的铝合金整体式车门内板深度进行了对标分析,提出了将零件的深度由171 mm降低至156 mm的方案,经CAE分析验证,铝合金整体式车门内板的合理深度参考值为150 mm。对钢、铝材质的理论回弹值进行了对比分析,计算出铝合金的回弹值为低碳钢回弹值的2.6倍。结论 通过对该门内板整个开发环节进行管控,形成了一套铝合金车门内板成形、回弹控制的模具开发体系;用首样件验证了整套开发方案的正确性,成功保障了该铝合金整体式车门内板的开发。     

燃料电池电极板材料工艺发展趋势

电极板是燃料电池的关键核心部件,起到分隔气体、提供反应界面、传导电流的作用。根据燃料电池应用工况的不同,电极板的材料选择与制造工艺路线也有所不同。材料工艺是决定燃料电池设计、质量、成本的核心要素。着重论述了金属、石墨、树脂作为电极材料的工艺路线。针对金属电极板材料,论述了车载、航空航天2种工况下不锈钢、钛材的成形设计准则、工艺路线、产品性能,并分析比较了不同成形方法中设备、模具工装和工艺路线的适用性。针对石墨电极材料,对比了硬石墨一次模压成形和柔性板石墨模压成形2种工艺,并根据各自的基材状态选择了合适的工艺路线,同时根据工艺路线的特点分析了产品的优缺点。在复合材料中主要选择了金属、石墨、树脂3种材料,根据制备原理,复合材料双极板有结构复合电极、材料复合电极和工艺复合电极3个研究方向。在结构复合电极方面,主要论述了石墨与金属复合的设计思路和结构特点;在材料复合电极方面,主要论述了热固性树脂和热塑性树脂与石墨复合的工艺路线和产品特点;在工艺复合电极方面,主要论述了微型燃料电池极板的制造理念和方法,并借鉴了微机械加工工艺路线,设计制造了复合工艺极板。最后展望了燃料电池电极板的箔材研发方向、级...     

鼓包竖板拉延成形的有限元模拟

简单介绍了铝合金板的冲压成形性能,应用有限元模拟技术,分别采用普通钢板和铝合金6009对鼓包竖板的拉延成形进行了有限元模拟,对比结果,分析了差异产生的原因.应用等效拉延筋,对材料采用铝合金板的模拟结果进行改进,较好地改善了起皱缺陷,最终提出了合理的工艺造型方案,为指导和改进拉延模结构设计提出可靠的理论依据及相关设计参数.同时,为该零件确定了合适的材料.     

Multi-objective Optimization of Sheet Metal Forming Die Using Genetic Algorithm Coupled with RSM and FEA

Present study describes the approach of applying response surface methodology (RSM) with a Pareto-based multi-objective genetic algorithm to assist engineers in optimization of sheet metal forming. In many studies, finite element analysis and optimization technique have been integrated to solve the optimal process parameters of sheet metal forming by transforming multi-objective problem into a single-objective problem. This paper aims to minimize objective functions of fracture and wrinkle simultaneously. Design variables are blank-holding force and draw-bead geometrical parameters (length and diameter). RSM has been used for design of experiment and finding relationship between variables and objective functions. Forming limit diagram has been used to define objective functions. Finite element analysis applied for simulating the process. Proposed approach has been investigated on a fuel tank drawing part and it has been observed that it is more effective and accurate than traditional finite element analysis method and the “trial and error” procedure.     

Thermo-mechanical sheet metal forming of aero engine components in Ti-6Al-4V—PART 2: Constitutive modelling and validation

In this work constitutive models suitable for thermo-mechanical forming of the titanium alloy Ti-6Al-4V are evaluated. A tool concept for thermo-mechanical forming of a double-curved sheet metal component in Ti-6Al-4V is proposed. The virtual tool design is based on finite element (FE) analyses of thermo-mechanical sheet metal forming in which two different anisotropic yield criteria are evaluated and compared with an isotropic assumption to predict global forming force, draw-in, springback and strain localisation. The shape of the yield surface has been found important and the accuracy of the predicted shape deviation could be slightly improved by including the cooling procedure. The predicted responses show promising agreement with the corresponding experimental observations when the anisotropic properties of the material are considered.     

Finite element modelling and experimental investigation of single point incremental forming process of aluminum sheets: influence of process parameters on punch force monitoring and on mechanical and geometrical quality of parts

New trends in sheet metal forming are rapidly developing and several new forming processes have been proposed to accomplish the goals of flexibility and cost reduction. Among them, Incremental CNC sheet forming operations (ISF) are a relatively new sheet metal forming processes for small batch production and prototyping. In single point incremental forming (SPIF), the final shape of the component is obtained by the CNC relative movements of a simple and small punch which deform a clamped blank into the desired shape and which appear quite promising. No other dies are required than the ones used in any conventional sheet metal forming processes. As it is well known, the design of a mechanical component requires some decisions about the mechanical resistance and geometrical quality of the parts and the product has to be manufactured with a careful definition of the process set up. The use of computers in manufacturing has enabled the development of several new sheet metal forming processes, which are based upon older technologies. Although standard sheet metal forming processes are strongly controlled, new processes like single point incremental sheet forming can be improved. The SPIF concept allows to increase flexibility and to reduce set up costs. Such a process has a negative effect on the shape accuracy by initiating undesired rigid movement and sheet thinning. In the paper, the applicability of the numerical technique and the experimental test program to incremental forming of sheet metal is examined. Concerning the numerical simulation, a static implicit finite element code ABAQUS/Standard is used. These two techniques emphasize the necessity to control some process parameters to improve the final product quality. The reported approaches were mainly focused on the influence of four process parameters on the punch force trends generated in this forming process, the thickness and the equivalent plastic deformation distribution within the whole volume of the workpiece: the initial sheet thickness, the wall angle, the workpiece geometry and the nature of tool path contours controlled through CNC programming. The tool forces required to deform plastically the sheet around the contact area are discussed. The effect of the blank thickness and the tool path on the punch load and the deformation behaviour is also examined with respect to several tool paths. Furthermore, the force acting on the traveling tool is also evaluated. Similar to the sheet thickness, the effect of wall angle and part geometry on the load evolution, the distribution of calculated equivalent plastic strain and the variation of sheet thickness strain are also discussed. Experimental and numerical results obtained allow having a better knowledge of mechanical and geometrical responses from different parts manufactured by SPIF with the aim to improve their accuracy. It is also concluded that the numerical simulation might be exploited for optimization of the incremental forming process of sheet metal.     

Radial basis functional model for multi-objective sheet metal forming optimization

Fracture and wrinkling are two major defects in sheet metal forming and can be eliminated via an appropriate drawbead design. This article proposes to adopt a multi-objective particle swarm optimization (MOPSO) approach, which differs from traditional multi-objective optimization with construction of a single cost function. MOPSO shows a certain advantage over other single cost function or population-based algorithms. While radial basis function (RBF) has shown considerable promise in highly non-linear problems, there has been no report in sheet metal forming design. Here RBF is attempted to establish the metamodels for fracture and wrinkling criteria in sheet metal forming design. In this article, a sophisticated automobile inner stamping case is exemplified, which demonstrated that RBF provides a better surrogate accuracy and MOPSO is more effective than the other methods studied. The use of RBF driven MOPSO procedure significantly improved the formability and can be recommended for sheet metal process design.     

板料数控渐进成形中变形力的研究

研究了板料数控渐进成形变形力的2种计算方法:按照纯剪切变形的方式计算变形力;按照剪切和弯曲综合变形的方式计算变形力。同时,通过实验测量出渐进成形的实际变形力。通过比较,实验测定的变形力与假定剪切弯曲变形计算的变形力相近,可以认为渐进成形是一种剪切弯曲变形。     

基于FEA的板料成形工艺优化及评价函数研究

基于有限元和优化方法的板料成形工艺优化设计技术已经成为新的研究热点,建立合理的评价标准以形成目标函数,从而用于评价冲压件的成形性是其关键技术之一.提出局部成形性、整体成形性和综合成形性评价函数.基于试验设计法,结合方盒形件拉深以及发动机罩外板成形,验证了本文提出的评价函数具有良好的可靠性和易用性.     

Effect of annealing on formability of aluminium grade 19000

Forming limit diagrams are used by the stampers to solve sheet metal forming problems. In practice, sheet metals have been subjected to various combinations of strain. Necking during sheet metal forming, sets the limit to which the sheet metal can be formed. Forming limit diagram is an effective tool to evaluate the formability of sheet metal in various strain conditions. The information upon the formability of the sheet metal is important for both sheet metal manufacturers and users. In this work, a study has been made on the formability of aluminium 19000 grades annealed at three different temperatures namely 160 °C, 200 °C and 300 °C for sheet thickness of 2.00 mm. The tensile properties and formability parameters were experimentally evaluated and they are related to forming limit diagram. Strain distribution profiles obtained from the forming experiment have been analyzed. The fractured surface of the formed samples were viewed using scanning electron microscope (SEM) and the SEM images were correlated with fracture behaviour and formability of sheet metal. The sheet which is annealed at 300 °C has been found to possess good drawability and stretchability compared to other two annealed sheets.     

Design and manufacturing of a human standardised hip cup out of titanium

Background: In recent years, the use of hip prostheses has become a routine procedure. Despite this experience and good clinical results different complications arise which have a negative influence on the lifetime of prostheses. Especially the migration or loosening of the hip cup prosthesis due to strain adaptive bone remodelling is still a problem. Patient‐individual prostheses represent a possible solution to this problem. Individual hip cups, however, are just implanted for the treatment of massive deformities or tumours. This study aimed at developing an innovative concept for the production of patient‐specific human hip prostheses made of titanium plates by sheet metal forming. Methods: For the realisation of this innovative concept, a reproducible design method for the generation of standardised human hip cup prosthesis was generated based on 13 original human geometries. By means of this methodology a hip cup was designed. Based on this design a human hip cup was produced by a developed high‐pressure sheet metal forming process. The development of the process was accompanied by a numerical preliminary design. Results: A comparison between the simulation and the fabricated hip cup leads to a standard deviation of 0.404 mm. Furthermore, an implantation of the prosthesis in a synthetic bone model shows a satisfactory fit accuracy at the edge of the prosthesis. Conclusion: The high‐pressure sheet metal forming process is suitable to manufacture the designed standardised hip cup. However, further optimisation is necessary.     

型材拉弯的力学与回弹分析

回弹是弯曲成形中普遍存在的现象,是由卸载过程中内力重新分布引起的,回弹的存在直接影响弯曲件的成形精度.本文针对转台拉弯成形过程,对等边型材等曲率拉弯进行了应力-应变分析,并按照卸载预拉力与不卸载预拉力两种情况对工件回弹进行了研究与探讨,得到两组半径回弹率理论曲线.通过与试验结果对比,不卸载拉力计算的结果与试验值比较吻合.     

板材电磁成形技术研究进展

电磁成形是一种典型的高速率成形技术,能显著提高材料的成形性能,并已经成功应用于金属板材成形领域,获得了很好的成形效果.为了能够继续扩大电磁成形技术在板材成形方面的应用,对目前板材电磁成形技术研究进展进行了综述.首先介绍了电磁成形工艺的原理与主要特点;分析了目前电磁成形技术、电磁辅助冲压成形技术在金属板材成形方面的研究进...