【作者】 陈高翔；

【导师】 郗向儒；

【作者基本信息】 西安理工大学 ， 机械设计及理论， 2010， 硕士

【摘要】 本文对型材滚弯成形过程及回弹进行了深入的研究,采用有限元方法对滚弯成形过程及回弹进行了数值模拟。首先介绍了型材滚弯的特点和应用,总结了国内外关于型材弯曲回弹问题理论研究的现状及发展趋势,阐述了论文的立题背景和意义。然后,对型材滚弯基本原理及滚弯过程中遇到的问题做了详尽的叙述。接着对滚弯成形过程中涉及到的材料、几何及接触三大非线性问题和影响回弹量的因素进行了分析和归纳,详尽阐述了型材滚弯成形回弹数值模拟的有限元方法,为后文的有限元模拟提供了理论基础。型材滚弯成形过程是一个动力学过程,因此采用显式和隐式算法相结合的有限元方法对Z形型材的滚弯成形加工过程和回弹进行了数值模拟,分析了型材滚弯回弹的应力、应变情况。揭示了型材厚度、滚弯半径、摩擦系数与型材回弹之间的影响规律,并研究了不同的型材厚度、滚弯半径、摩擦系数在滚弯成形过程中的应力、应变情况,以探求回弹的内在作用机理。对型材成形性能和壁厚进行了模拟,从而改善成形过程。为了探求多因素对型材回弹共同作用的情况,进行了正交模拟试验,确定了各因素对型材回弹影响的主次,并对型材回弹工艺参数进行了初步优化。在此基础上为了减少型材滚弯成形有限元模拟的时间,组建了BP神经网络。并对减小回弹的几种工艺措施进行了初步的研究,对提高滚弯成形零件的加工精度具有一定的指导意义。更多还原

【Abstract】 This thesis studied the profile extrusion roll bending forming process and springback intensively, and did numerical simulation for the process, using finite element method.First, the thesis introduced the character and application of the profile extrusion roll bending, and concluded the current situation and development of the topic that the profile extrusion roll bending and springback home and abroad. It also elaborated on the background and significance of the topic.Then, it made an exhaustive statement to the basic theory of profile extrusion roll bending and the problems met during the roll bending. After that, the thesis analyzed and generalized three nonlinear problems (materia nonlinearity、geometrie nonlinearity and contact boundary nonlinearity) and the factors which affects the values of springback. Finite element method was elaborated intensively, which laid a theory basis for finite element simulation in the next paragraph.The profile extrusion roll bending process is a dynamic one, so the thesis adopted the finite element method combined the explicit with the implicit algorithm, to do numerical simulation for Z profile roll bending process. It showed the influence law.the profile thickness、roll bending radius、friction coefficient during springback. And it researched stress-strain at different profile thickness, roll bending radius, friction coefficient in the roll bending process to study the intrinsic springback mechanism.Did simulation for forming function and wall thickness,thus make the forming process much better.To research how multifactor act on the profile extrusion roll bending in chorus, the thesis made orthogonal simulated experiment. As a result, it fixed the different roles various factors played and made preliminary technological parameter optimization in the roll bending process on which BP Neural Network has been built to shorten the time the finite element simulation. It did preliminary research on several technological measures which depress the springback, and it has directive significance on advancing the processing precision of the roll bending forming.更多还原