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Establishment of Fractal Approach in Metal Forming (Development of Simulator Predicting Surface Profiles of Press-Formed Products)

金属成形中分形方法的建立（预测压制成形产品表面轮廓的模拟器的开发）

基本信息

批准号：
12650115
负责人：
KUROSAKI Yasushi
金额：
$ 2.05万
依托单位：
Mie University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

In metal forming operations, there are many surface phenomena and problems which are very complicated and difficult to characterize quantitatively by the usual mathematical methods. As a measure to overcome such problems, a fractal approach was introduced in the present investigation. In the beginning, a practical fractal method applicable to various surface phenomena was proposed. Next, it was aimed to develop a simulator which can predict free surface profiles of any press-formed products and thus serves to provide such surface information as needed for process design. Finally, various applications of the fractal approach were presented. Main results obtained are as follows.1. Fractal Characteristics of Free Surface Profile of Sheet Metals under Biaxial TensionTwo fractal analyses applicable to metal sheets and other objects were presented. The uniaxial and biaxial tension test that caused various strain ratios were conducted on metal sheets, and their free surface were examined by e … More mploying those fractal analyses. An important rule was found that the fractal dimension of surfaces is uniquely determined from the equivalent strain independently of the strain (or stress) ratios.2. Development of Simulator for Prediction of Free Surface Profiles of Sheet-Formed ProductsA method for simulating the surface roughening phenomenon caused by plastic deformation is presented. The strain dependence of the fractal parameters required for simulation can be unifiably expressed with the equivalent strain, irrespective of the strain ratio. Based on the result, a simulator for predicting surface profiles of any press-formed products is proposed, and shown to be valid.3. Various Applications of Fractal ApproachThe fractal approach was applied to characterization of adhesion particles caused on the tool surface in forging, a quantitative estimation of fracture surfaces for mild steel and an analysis of the nanofractal structure of material surfaces. Thus, the fractal analyses developed in the present investigation was shown to be useful. Less

在金属成形过程中，存在着许多表面现象和问题，它们非常复杂，难以用常用的数学方法定量描述。作为一种措施，以克服这些问题，分形方法被引入在本调查。首先，提出了一种适用于各种表面现象的实用分形方法。其次，它的目的是开发一个模拟器，可以预测任何压制成型产品的自由表面轮廓，从而提供所需的工艺设计的表面信息。最后，介绍了分形方法的各种应用。主要研究结果如下：1.双向拉伸下金属板材自由表面轮廓的分形特征提出了两种适用于金属板材和其它物体的分形分析方法。对金属薄板进行了不同应变比的单轴和双轴拉伸试验，并对自由表面进行了电子探针检测， ...更多信息利用这些分形分析。发现了一个重要的规律，即表面的分形维数由等效应变唯一确定，与应变（或应力）比无关.板料成形自由表面轮廓预测模拟器的研制提出了一种模拟塑性变形引起的表面粗糙化现象的方法。模拟所需的分形参数的应变依赖性可以用等效应变统一表示，而与应变比无关。在此基础上，提出了一种适用于任意形状冲压件表面轮廓预测的模拟器，并验证了该模拟器的有效性.分形方法的各种应用分形方法被应用于表征锻造工具表面上产生的粘附颗粒，定量估计低碳钢的断裂表面和分析材料表面的纳米分形结构。因此，在本调查中开发的分形分析是有用的。少