【作者】 孙家军；

【导师】 金霞；

【作者基本信息】 南京航空航天大学 ， 材料加工工程， 2008， 硕士

【摘要】 单轴柔性滚弯是一种先进的、高度柔性的钣金制造工艺,与传统的弯曲方法相比,生产的弯曲件具有强度高、表面质量好、成本低等特点,特别适用于航空航天及汽车工业中小批量甚至是单件零件的生产。本文详细地介绍了单轴柔性滚弯技术,主要研究工作如下:1.根据单轴柔性滚弯成形技术原理,在实验室现有设备数控渐进成形机床的基础上,设计滚弯U型截面型材的滚弯装置。实验研究表明,单轴柔性滚弯系统存在一临界进给量,当进给量超过该值后,工件弯曲曲率半径不再随进给量的增大而变小,达到一个极限半径,并且该半径与刚性滚的直径成正比。2.从单轴柔性滚弯过程受力分析方面着手,在对工件受力与变形情况进行一些假设简化的基础上,根据弹塑性理论提出了描述单轴柔性滚弯U型截面型材的理论模型,获得了工件回弹后曲率半径与各个主要影响因素之间的理论公式。3.在有限元分析当中,常用应变能函数描述橡胶材料的力学性能。本文对橡胶类材料的常用应变能函数进行了描述,以“Mooney-Rivilin”模型为本文有限元分析中橡胶的本构模型,利用单轴拉伸和单轴压缩实验数据拟合“Mooney-Rivilin”模型的两参数。4.利用有限元软件MSC.marc建立了单轴柔性滚弯U型材模型,并对成形及回弹过程进行了有限元模拟仿真。根据有限元计算结果,对影响工件回弹成形的参数进行了分析,验证了实验中得出的柔性滚弯技术的重要特征,与实验结果对比表明,有限元分析具有较高的精度,有一定的实际应用价值。更多还原

【Abstract】 Single-Axle Bending Technique with Elastic Rubber(SABTER) is an advanced and highly flexible manufacturing technology for sheet metal forming. Compared with the traditional bending method, the products of bending have the advantages of high strength, good surface quality and low cost. It is especially suitable to aerospace and automobile industries with single or mini-batch production.In this study, the principle of the technique is discussed comprehensively. The main work and results in this dissertation can be concluded as follows:1、According to the principle of the SABTER, a U-profile roll bending device which is based on NC incremental forming machine tools is designed. The experimental research indicates that SABTER has a critical feed .The radius of curvature is no longer changed with the feed increasing when the feed exceed the critical feed. A limit radius that is proportional to the diameter of the rigid roller may be obtained.2、Based on the force analysis of the SABTER and a series of simplifying for the stress and deformation of the workpiece, a theoretical mould that describes the flexible roll bending the U-profile is proposed by the description of elastic-plastic theory.With this theoretical mould, the formula about the curvature radius of the workpiece and the major influencing factors have been found.3、In finite element analysis, the mechanical property of rubber material is always described by strain energy function. In this paper, some commonly used strain energy functions of the rubber are described. The“Mooney-Rivilin”material model is used in FEA. Data of Uniaxial tension and compression tests are inputted into Msc.marc software package to compute the two parameters of Mooney-Rivilin material model.4、The FEA model of the flexible roll bending U-profile has been built with the FEA software Msc.marc. The loading and Springback process have been simulated. With the results of FEA, major factors related to springback have been analyzed and the important feature of SABTER from experiment has been verified. Compared with the experimental results, it shows that the simulation has a good precision and the FEA mode has a certain practical application value.更多还原