成形的

The results of prediction agree well with the experimental ones. It proves that the thermo-mechanical analysis、the neural network models of flow stress and microstructure as well as the numerical simulation system developed combining coupled thermal-mechanical rigid-viscoplastic FEM with BP neural networks are reliable to describe the hot back extrusion process of Ti15-3 alloy truly. The simulation system has good prediction capacity for the microstructure evolution of Ti-15-3 alloy during hot backward extrusion and after solution treatment. It can be used to replace the experiments for predicting the flowing laws and the distribution of microstructure.

由此证明，本文的热力耦合理论分析、流变应力及显微组织的神经网络预测模型以及采用三维热力耦合刚粘塑性有限元与三层向后传播的人工神经网络相结合的方法开发的Ti-15-3合金筒形件热反挤成形的显微组织数值模拟系统是可靠的，能够真实地描述Ti-15-3合金热反挤工艺过程，并对其反挤成形及固溶处理后的显微组织具有很好的预测能力，可以被用来代替预测其反挤成形规律和组织分布情况的试验。

They had been widely used in the automobile parts. The raw material of hydroforming parts was tubes.

液压成形技术中使用的原材料为钢管，近年来利用激光焊管作为液压成形的原材料，得到了迅速发展。

To establish the constitutive equation of material, the metric tensor for stress , strain and their transformation equations between different configurations are derived, and basic theory of finite deformation as well as elasto-plastic deformation criterion are studied. By analyzing the applicability of different element models, four-node quadrilateral degenerated Mindlin isoparametric element is adopted because of its good versatility, and the element stiffness matrix is derived. The static implicit elasto-plastic finite element equation for complex skin stretch-forming is put forward based on Updated Langrange formulation.

本文首先系统地阐述了有限变形的相关基本理论，针对板料成形建立了应力应变度量张量及其相应的转换关系；介绍了材料的屈服准则、塑性变形强化规律、塑性流动规律以及加、卸载准则，并在此基础上建立了有限变形各向异性弹塑性本构方程；对板料成形的单元模型进行了分析，针对飞机蒙皮零件特点，采用通用性强的四节点四边形退化Mindlin等参壳单元进行成形模拟，并导出其单元刚度矩阵的具体形式；基于以上研究，以逐级更新Langrange描述的持续虚功率原理为基础，建立了率形式的复杂蒙皮拉形过程静态隐式弹塑性有限元方程。

ABSTRACT Sheet metal forming is an important forming process, which is widely used in mechanical industry.

钣料成形是金属成形的一种重要方法，在机械制造业中获得广泛应用。

A method and device for continuously supplying drops into female moldings which are rotatingly movable for manufacturing moldings, wherein synthetic resin in molten condition extruded from an extrusion opening is cut by a cutter attached to a holding mechanism to form the molten resin into drops in a determined quantity, the drops are held and conveyed by the holding mechanism, and the drops are forcibly inserted and supplied into the concaves of the female moldings.

是一种将用于对成形品进行成形的滴物向旋转可动的形成阴模连续供给的方法及装置，将从挤压开口部挤压出的熔融状态的合成树脂通过附设在保持机构上的切断工具切断、形成定量的滴物，利用保持机构将滴物保持输送，向成形阴模凹部强制插入、供给。

In process of spinning,The winding formation depends directly on the up and down movement of ring bar,especially the repeated bumping and beating of nose bit and nose base on the formation cam.

在纺纱过程中，钢领板的上下运动直接影响到卷绕成形的质量，特别是成形凸轮在桃尖的冲击及桃底的打顿，更突出地影响到成形的好坏。

Combined hourglass control in analysis of cold ring rolling process;2. Recent status and development of real-time measurement and online control technology in cold ring rolling ;3. The influence law of feed rate of idle roll on the quality of end face of ring,axial width spread ratio,roll force,roll moment and metal flow characteristic in cold ring rolling process has been explored through the FEM numerical simulation of the ring with rectangular cross-section based on the elastic-plastic dynamic explicit FEM under the Abaqus software environment.

基于Abaqus/Explicit提供的显式动力学有限元算法，对矩形截面环件冷辗扩进行了有限元数值模拟，揭示了芯辊进给速度对环件冷辗扩过程中环件端面质量、轴向宽展率、辗扩力、辗扩力矩以及金属流动特性的影响规律，并从金属塑性成形原理和塑性加工力学等角度对这些规律进行了合理的解释，从而获得了进给速度对冷辗扩成形的影响规律，为环件冷辗扩在实际应用中进给速度的选择提供了依据，对揭示冷辗扩成形机理也具有十分重要的意义。

The influence law of feed rate of idle roll on the quality of end face of ring,axial width spread ratio,roll force,roll moment and metal flow characteristic in cold ring rolling process has been explored through the FEM numerical simulation of the ring with rectangular cross-section based on the elastic-plastic dynamic explicit FEM under the Abaqus software environment.

基于Abaqus/Explicit提供的显式动力学有限元算法，对矩形截面环件冷辗扩进行了有限元数值模拟，揭示了芯辊进给速度对环件冷辗扩过程中环件端面质量、轴向宽展率、辗扩力、辗扩力矩以及金属流动特性的影响规律，并从金属塑性成形原理和塑性加工力学等角度对这些规律进行了合理的解释，从而获得了进给速度对冷辗扩成形的影响规律，为环件冷辗扩在实际应用中进给速度的选择提供了依据，对揭示冷辗扩成形机理也具有十分重要的意义。

The effect of the friction between rolls and ring can be ignored and the effect of the spread velocity of rolling on the deformation of ring is illustrated.

通过模拟分析比较，揭示出了环件轧制过程中的金属流动规律：轧制时，环件外侧的变形最大，厚向中心部位变形最小，内侧的变形程度介于中间；环件内外环面的压应力分布和变化规律：在垂直于环件轴线的对称面上，压应力分布近似对称状态，而且在对称面上的应力最大，往端面方向开始减小；指出了环件轧制中轧辊与环件摩擦对环件成形的影响：对于环件的宽展变形，摩擦的影响很小，可以忽略；分析了环件进给速度对环件成形的影响并阐述了环件厚向中心部位凹陷产生的原因，提出防止凹陷的措施：在轧制时，尽量使用快的进给速度有利于防止端面凹陷的产生；研究了导向辊位置对环件成形以及轧辊受力的影响：导向辊的位置对环件的宽展变形影响很小，但对轧辊的受力影响较大，当导向辊的中心位置位于毛坯初始中心位置之上时，驱动辊和芯辊的受力相对较小，这是导向辊导向时优先考虑的位置。

Multi-point forming experiments of titanium cranid protheses show that precision of the workpiece is improved significantly via the closed-loop multi-point forming method. And precision digital forming for sheet metal parts is accomplished based on multi-point forming techniques and rapid laser scanning measurement.

结果表明，基于快速测量的曲面多点成形精度控制技术充分利用了多点成形的快速性的特点，通过三维空间形状反馈，来提高多点成形的精度。

The good news is that after formatting from the command line to FAT32 (format /fs:fat32 /a:4096 drive:) all but one of the problematic games that I tested work perfectly.

好消息是，从指挥线后格式化了FAT32(格式/曾荫权：了FAT32/答：4096年径：)所有问题，但其中的游戏测试工作，我很好。

In Amsterdam. He is a Dutch painter, draftsman, and etcher of the 17th century, the greatest artist of the Dutch school, a master of light and shadow whose paintings, drawings, and etchings made him a giant in the history of art.

伦勃朗是一位17世纪画家、绘图家、版画家，荷兰学派的最伟大艺术家，他的明暗法的大师，他的绘画、素描和版画使他成为一位艺术史上的巨匠，其画作体裁广泛，擅长肖像画、风景画、风俗画、宗教画、历史画等。