汽车覆盖件冲压工艺设计KBE系统中的知识表示技术

根据汽车覆盖件冲压工艺设计的特点 ,阐述了与汽车覆盖件冲压工艺设计有关的不同类型知识的表示方法 ,主要有一阶谓词逻辑、语义网络、产生式规则、框架和剧本、可视化文本和图象 ,以及面向对象的方法等 ,并比较了各种方法的优缺点。面向对象的集成知识表示等方法成功地应用于汽车覆盖件冲压工艺设计KBE系统的知识表示     

大型覆盖件上孔的冲压

通过工艺分析,揭示了大型覆盖件上孔的冲压成形中冲压变形的基本规津,同时给出了确定工艺冲孔的形状与尺寸的有效的方法。     

覆盖件模具特征约束模型及其应用

针对覆盖件模具设计的复杂性、灵活性、经验性、模糊性．提出了一种基于特征的分层的约束模型。覆盖件模具特征分为冲压工艺特征、功能组合特征和基元特征三个层次，与此相应建立了分层的约束网，并叙述了其推理过程。     

长安牌微型汽车覆盖件模具设计

微车生产关键之一,是驾驶室、车身覆盖件的成形工艺。汽车覆盖件是构成驾驶室和车身的异形体表面零件,它表面带有装饰性,如连贯的装饰棱线,筋条及装饰坑凹等都要求美观大方。覆盖件的材料由厚度0.8～1.2mm的08F或08Al的冷轧钢板冲压而     

引进日本汽车冲压模具的消化吸收技术成果鉴定会在江西召开

引进日本汽车冲压模具的消化吸收课题是江西省1993年重点科研项目。因为汽车零件,尤其是汽车覆盖件的冲压技术是汽车生产的关键性技术,同时也是为了更好、更全面的消化从日本引进的先进模具和技术,加速模具技术人材的培养,尽快在汽车覆盖件生产技术上赶上发达国家水平。 该课题由南昌大学与江西省江铃汽车股份有限公司共同完成。他们对从日本全面引进的汽车车身全套冲压模具和技术资料进行了系统的分析和研究,包括图纸资料的转化,冲压工艺和模具结构特点的分析,模具制造、安装调试要点的说明等一系列工作。为了达到更好吸收国外先进技术,并扩大使用范围,他们编写了三十万字的“国外     

前地板工艺分析及修边冲孔模具设计

介绍了冲压上常见的大型覆盖件的冲压工艺方案的确定过程 ,并以S0 1农用皮卡车“前地板”为例 ,针对此件外形复杂 ,成形深度大 ,模具加工周期大 ,成本高等问题 ,进行了详细的冲压工艺分析 ,确定了合理的冲压工序 ,且着重介绍了修边冲孔模具的设计要点及简化模具加工工艺 ,降低模具成本 ,缩短制模周期等措施     

顶盖整形工艺分析及模具设计

介绍了汽车上常见的外覆盖件冲压工艺方案的确定过程，并以“郑州尼桑”轻型皮卡“顶盖”为例，针对此件成形难，取件难这一难点，确定了合理的冲压工序为拉延、修边、翻边、整形。且着重介绍整形模具的设计要点及整形以后顺利取件等措施。     

板料成形拉延筋技术研究现状

拉延筋在汽车覆盖件拉深成形中起着十分重要的作用。利用拉延筋可以调节和控制板料的变形程度和变形分布,抑制破裂、起皱、面畸变等多种冲压质量问题的产生。在很多情况下,拉延筋的设置合理与否将决定覆盖件拉深的成败。较系统地总结了板料成形拉延筋技术以及拉延筋作用原理、阻力模型、影响因素等的研究现状。     

汽车门槛内板零件冲压数值模拟及参数优化

针对汽车覆盖件冲压变形复杂,成形工艺参数难以确定等特点,基于DYNAFORM软件对汽车门槛内板零件的拉延成形过程,及不同工艺参数对成形结果的影响进行了研究。用优化的工艺参数进行模拟验证,从而为工艺设计和试模提供理论指导。     

材料参数及工艺参数对盒形件成形性能的影响研究

主要研究了材料参数及工艺参数对盒形件成形性能的影响 ,通过正交试验和计算机数值模拟相结合 ,确定了最佳的参数组合方式 ,并用该最优数据进行实际冲压 ,得到的结果与最优模拟结果比较吻合     

滚动轴承座密封罩成形工艺及模具

分析了密封罩零件冲压成形的难点,论述了采取的有效工艺措施和模具设计要点。     

LDR and hydroforming limit for deep drawing of AA5754 aluminum sheet

The goal of the research was to determine the limits and conditions in which the sheet hydroforming process provides a significant advantage over stamping in deep drawing of AA5754 aluminum sheets. Specifically, the maximum draw depth achievable by stamping, warm stamping (WF), sheet hydroforming (SHF), and sheet thermo-hydroforming (THF) of AA5754 aluminum alloy were quantified through experimental and computational modeling. A limited number of forming experiments were conducted with AA5754 aluminum sheets using a cylindrical punch and counteracting fluid at different temperatures and pressures. Several parameters, such as force–displacement, hydroforming pressure and temperature, and the maximum draw depth prior to wrinkling or tearing were measured during the forming process to make comparisons with simulations. The computational study included the simulation of stamping, WF, SHF and THF of AA5754 aluminum sheet with the LS-Dyna code, and the Barlat 2000-2d yield function with temperature-dependent coefficients. To predict the onset of wrinkling and tearing, the numerically generated, temperature-dependent forming limit diagrams (FLDs) based on the Barlat 2000-2d yield function were used. It was found that compared with stamping, SHF and THF can achieve more than 100% deeper draw depths with AA5754 aluminum sheet. The stamping simulations were used also to calculate the optimum blank size and die corner radii for the limiting draw ratio (LDR). The LDR was found to be very sensitive to the punch and die corner radii used in the experiments, which represent the curvature of character lines in an actual part. The LDR for AA5754 aluminum sheet was found to be 1.33 and 2.21 for sharp and round die corner radii, respectively. Overall, it was concluded that SHF is most ideal for deep drawing of aluminum sheets with sharp radii features. With the additional drawability provided by SHF, the automotive industry would be able to make difficult-to-form aluminum parts that cannot be stamped without product concessions such as increasing the die radii.     

Warm forming die design,part I: Experimental validation of a novel thermal finite element modeling code

Finite element analysis (FEA) has become an invaluable tool in the design of sheet metal stamping dies and processes. FEA has gained widespread acceptance as the best method of optimizing dies for conventional stamping processes. More recently, FEA has been shown to be an effective method of designing tooling for sheet forming processes. In this work, an FEA based approach is applied to the warm stamping (warm forming) process. This work introduces a new thermal finite element analysis software called PASSAGE®/Forming (PASSAGE) that enables the up-front design of the thermal management of warm forming dies. This thermal finite element analysis software is designed to specifically handle the forming and optimization scenarios related to the heating of a stamping die while minimizing user interface time. In this work, PASSAGE has been applied to a simple block of steel embedded with cartridge heaters to validate the prediction capability of this software under two different heating conditions. The results show that PASSAGE is capable of predicting the actual steady-state temperature distribution within the block with an acceptable level of accuracy while yielding notable information to the user with respect to specifying power requirements. A finite element software package like PASSAGE is a valuable tool that will aid greatly in the implementation of warm forming as a manufacturing process beyond the scope of the laboratory and into production.     

有限元分析技术中的断裂判断

有限元法分析技术在高精密冲压行业中已经广泛应用。它具有分析材料流动 ,应变 ,应力及冲压负载的功能。通过有限元法分析可减少试模次数 ,从而降低消耗 ,缩短模具设计时间。但在有些情况下 ,它并不能准确的告诉我们在冲压过程中何时产生断裂。阐述了几则断裂判据以及它们的特点和在有限元分析技术中的应用     

特大型铝合金锥环的冲压成形

在简要分析了某特大型铝合金锥环原有的铸造 车削制造工艺存在不足的基础上 ,指出对其采用板料冲压成形的必要性。应用冲压工艺理论 ,计算出了相应的冲压工艺参数。通过进一步分析确定出了两种合理的冲压成形方案 ,并巧妙地解决了该特大型铝合金锥环实际冲压时设备行程不足的问题     

集成于冲压产品模型的工艺性评判方法研究

针对传统设计方法的缺陷 ,提出了集成于产品建模的冲压工艺性评价方法 ,分析并提出了结构工艺性与精度评价中关键技术的对策。     

润滑条件对超深冲IF钢成形性能的影响

研究了不同润滑条件下钢板FLD和LDH的变化规律。研究结果表明 :润滑影响了钢板冲压成形过程中的应变路径 ,但对FLD0 没有影响 ;润滑对LDH0 影响显著。     

Micro fabrication on cylinder surface for control of wettability

A micro fabrication is presented to control wettability on cylinder surfaces. A machine tool is developed to form the micro-scale structure on the cylinder in incremental stamping. The stamping tool is manufactured with fabricating the micro-scale structure on the top of the tool in FIB sputtering. The micro incremental stamping is repeated with linear motion of the tool and rotation of the workpiece. The rotation is controlled by the friction drive on the machine table because of the stable stamping with reducing bending of the workpiece. The critical stamping depth, the minimum depth in which the structure is formed, is determined in the forming tests using the structured tool. Then, a stripe type structure is formed to control wettability on the cylinder surface. Anisotropic wettability appears on the structured surface.     

板料冲压成形中坯料优化设计方法研究

较为系统地介绍了冲压件坯料的优化设计方法 ,并比较分析了其各自的优缺点。相比于其他方法 ,一步模拟方法效率高、适应面广、功能较强 ,可以在产品的设计之初提供较为丰富的信息。因此 ,对其作了较为详细的论述。实例证明 ,一步模拟法可用于板料成形工艺方案的快速评价及参数优化。