Lesson 1 Position of metal forming in modern industry 金属成形在现代工业中的地位Metal forming is one of the fundamental manufacturing process. It plays an important part in metallurgy冶金, machine building机械制造, power电力, autobile汽车, railroad, aerospace航空, ship-building, weapon, chemical化工, electronics电子, instrument and meter making仪器和仪表制造and light industries轻工业.金属成形是材料的塑性加工过程在金属成形工艺中，最初的简单零件, 坯料或板料通过在模具之间变形而获得所需零件的最终形状由于模具具有所需零件的几何形状， 通过模具内表面对变形材料施压，简单形状的零件就会变成复杂形状的零件金属成形很少产生废料甚至不产生废料， 并且往往在很短时间内（即压力机或锻锤的一次或几次行程中）形成产品形状。
因此， 金属成形可节能省材特别是在大中批量生产时，模具成本容易收回另外，对于给定重量的零件，用金属成形加工比用铸造和切削加工生产具有更好的力学性能、冶金性能和可靠性At present, net shape manufacturing净形制造and near net shape manufacturing近净形制造have become the focus of studies研究的焦点pursed追逐by the metal forming circle领域.Research institutions研究学会，研究机构concentrating on the study of net shape manufacturing净形制造have been established建立 and enormous巨大funds and minds财力与智力invested. Net shape manufacturing is vigorously developing throughout the world.By the application of cold extrusion冷挤压, cold heading冷镦, precision die forging精密模锻, special rolling特殊滚压, fine blanking精冲, spinning旋压, multi-ram forging多向模锻, multi-position pressing 多工位压制, high-speed pressing with progressive dies级进模高速冲压, powder forging粉末锻压, super plastic forming超塑性成形and laser processing激光加工, finished parts can be produced with high accuracy高精确度, low surface crudeness粗糙度.The days have already gone when （定语从句）metal forming was considered 认为as a process by which only 认为as a process by which only semifinished products could be made（从句）.It is predicted 预测by … that（从句）by the year 2000 metal forming combined with the year 2000 metal forming combined with grinding technology（定语）磨削工艺will replace most of metal cutting.Lesson 2 Classification of Metal Forming ProcessesNearly all mental forming processes involve the workpiece being subjected to complex stress states(处于复杂应力状态下)which can vary from, say triaxial compression(三向压应力) to biaxial tension(两向拉应力). However, shear stresses(剪切应力) need not be considered unless they constitute(构成) major stresses to which the workpiece is subjected and are thus influential in contributing to plastic deformation. Most of the complex stress states can be approximated(近似) by their principal stress components(主应力),that is, by the normal stress(正应力) acting on planes on which shear stresses(剪应力) are absent.Squeezing group（压缩类）in which the workpiece is subjected principally to a compressive stress state（压应力状态）.The processes in this group normally involve bulk plastic deformation（大塑性变形）producing considerable change in the shape of the workpiece（形状发生显著变化）.They include forging ( upsetting顶锻, closed die forging闭式模锻and coining 压印), forward and backward extrusion（正反挤压）, rolling滚压, swaging（型锻, 模锻）, spin forging旋锻and rotary forging摆动辗压.Drawing group in which the workpiece is subjected principally to a tensile stress（拉应力）state; thus pulling instead of pushing（后置定语）is谓语implied.The processes in this group are generally limited（通常受限）in the extent of plastic deformation（塑性变形量）of the workpiece which（定语从句）can be achieved in a operation（单次操作所能达到的）and are therefore（因此）restricted to changes in shape of the workpiece rather than changes in thickness. The workpiece is thus usually in the form of metal sheet金属片, plate or thin walled tubing薄壁管. This group includes sheet, wire and bar drawing, tube drawing管材拉拔, the deep drawing深拉延of cylindrical cup筒形杯and box shapes盒形件and stretch forming.Bending group in which （修辞group）the workpiece is subjected to couples力偶thereby including（修辞group）tensile stresses拉应力on one side of the workpiece and compressive stress压应力on the other with a stress gradient throughout应力梯度 the thickness of the workpiece.This group（主语）of processes are （谓语）again restricted to change of shape rather than 两者相比较changein thickness and include （谓语）straight flanging直翻边, stretch flanging ( concave flanges)拉伸翻边（凹板翻边）, shrink flanging (convex flanges)收缩翻边（凸板翻边）and the seaming卷边of sheet or plate.Cutting group are those processes which either separate excess metal from the workpiece in a single operation单次操作 or by incremental（增量，逐步）metal removal.The first category are shearing processes剪切工艺such as bar cropping棒料剪切, and piercing冲孔and blanking落料of sheet mental金属板which are regarded as chipless forming processes 无屑成形工艺. The second category are chip forming有屑成形and include the conventional传统machining processes机加工工艺 such as turning车, drilling钻, milling铣, grinding磨, sawing锯, broaching拉削and shaving刨削.tensile ：拉应力compressive ：压应力shear：剪切力Chip forming:有屑成形Strain－rate：应变速率 Piercing：冲孔Blanking：落料Turning：车Drilling：钻Milling：铣Grinding：磨Sawing：锯Broaching：拉削Shaving：刨削Couples：力偶flanging：翻边、折边Lesson3 有限元优化的应用 在结构日益复杂的情况下，当工程师们工作时，他们需要合理的、可靠的、快速而经济的设计工具。
过去二十多年里，有限元分析法已经成为判别和解决涉及这些复杂设计课题时的最常用方法 因为工程中的大多数设计任务都是可定量的，所以实践上，为了快速找到一些可供选择的设计方案计算机令繁琐的重复设计过程发生了深刻的变革但是，即使是现在，许多工程师仍然使用人工的试凑法这样一种方法使得即使是很简单的设计任务也变得困难，因为通常它要花更长的时间，需要广泛的人—机交互配合，且偏于用设计组的经验来设计优化设计是以理论数学的方法为基础，改进那些对于工程师来说过于复杂的设计，使其设计过程自动化如果在一部台式计算机平台上能实现自动优化设计，。