Modelling and Simulation of Machining Processes 金属切削数值模拟的复杂性

2010-10-13 17:29:03 作者:huright 来源: 浏览次数:0

Metal cutting is a process in which, by action of a cutting edge (or edges) of a tool, unnecessary material is removed. It is one of the most common manufacturing processes for producing parts and obtaining specified geometrical dimensions and surface finish. Turning, drilling, and milling are examples of different industrial applications that use this principle with different geometry and number of cutting edges. Nevertheless, in the current work, the analysis is restricted to models that describe the local behaviour due to one cutting edge. These models can be used to increase the knowledge of the cutting process and improve it. Understanding of the material removal process in metal cutting is important in selecting tool material and design and in assuring consistent dimensional accuracy and surface integrity of the finished product. Although mechanical cutting is one of the most widespread processes, the modelling and simulation of this phenomenon is by no means trivial. It has proved to be particularly complex due to the diversity of physical phenomena involved, including large elasto-plastic deformation, complicated contact/friction conditions, thermo-mechanical coupling and chip separation mechanisms. One factor that has caused considerable difficulty and frustration to researchers investigating the chip formation is the fact that the phenomena occurring in the vicinity of the cutting edge are highly localized and not directly observable. After more than a hundred years of research, the study of metal machining still constitutes a current challenging task. Although the first theoretical models were able to describe the problem only qualitatively, their principles and assumptions laid foundations for further advancements. The main shortcoming of existing solutions for chip formation mechanisms perhaps lies in the oversimplification and consequent disregard of the complex interplay of the different parameters. Numerical simulation by the finite element method has proven to be a reliable alternative to analyse several metal forming operations. Nevertheless, only recently, with the advent of high-speed computers and robust large-strain/large-displacement procedures, contact/fracture algorithms, adaptive re-meshing procedures for inelastic problems and robust finite/discrete algorithms, have numerical simulations of forming operations,
金属切削是一个过程,其中,通过切割行动 
边缘的工具(或边缘),不必要的材料将被删除。 
是最常见的生产制造工艺之一 
零件几何尺寸和获取指定 
和表面光洁度。车削,钻孔和铣削的例子 
使用不同的工业应用这一原则 
不同的几何形状和切削刃数。不过, 
在当前的工作,分析仅限于 
模型描述的局部行为,由于一切 
边缘。这些模型可以用于增加知识 
在切割过程和改进。了解有关 
金属切削材料去除过程是重要的选择 
刀具材料和设计,在确保一致 
尺寸精度和表面完整性完成 
产品。 
虽然机械切割是一种最普遍的 
流程,建模和模拟这种现象 
绝不是微不足道的。它已被证明是特别 
由于复杂的物理现象所涉及的多样性, 
包括大型弹塑性变形,复杂的 
接触/摩擦条件下,热机械耦合 
和芯片分离的机制。有一个因素 
造成相当大的困难和挫折的研究人员 
调查该芯片的形成是一个事实,即现象 
发生在尖端附近的高度 
局部的,不能直接观察到。经过逾一百多 
多年的研究,金属加工研究还 
构成了目前具有挑战性的任务。虽然第一次理论 
模型能够描述问题只定性, 
他们的原则和假设奠定了基础 
进一步的进展。对存在的主要缺点 
对于芯片解决方案的形成机制可能在于 
随之而来的简单化和不顾复杂 
相互作用的不同参数。数值模拟 
通过有限元方法已被证明是一个可靠的 
分析几种替代金属成型操作。 
然而,只有最近,在高速的到来 
电脑和强大的large-strain/large-displacement程序, 
接触/骨折算法,自适应重新啮合程序 
非弹性的问题和强大的有限/离散算法, 
已形成业务数值模拟。

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