薄规格板带材浪形矫直实验模拟研究

发布时间：2018-07-29 19:19

【摘要】：随着家电、国防、航天等工业的迅猛发展,尤其是我国轿车行业的飞速进步,市场对薄规格板带材的需求量越来越多,质量要求也越来越高。对于有浪形的板带材,当经过辊式矫直机时,浪形会不断的延展压缩,板带材内的残余应力会不断加载与卸载,达到矫直浪形与均衡分布残余应力的效果。当前,对于中浪、边浪等不可展开板形缺陷的矫直研究没有形成完善的系统理论,尤其薄规格金属板带材板形缺陷复杂,对矫直模型和技术的研究更加困难。本论文选取了中浪进行针对性的研究,来得到浪形的矫直规律。考虑实际条件的限制,在研究中对中浪进行了简化,取一块板材上的单独中浪进行研究,把中浪看作板材局部的瓢曲变形,这样便于制作想要的浪形效果。在实验中根据中浪的特点对其进行了浪高、浪宽、波长三个参数进行了定义,围绕不同参数的浪形进行各项对比。得到以下几点结论:(1)通过矫直对比可以得出浪高与波长对浪形的矫直效果影响较大,浪高、波长越大其矫直难度越大。对于浪高过大的浪形,在矫直后会在原浪形区域形成连续的微型浪,且其波长近似为矫直机辊距的二分之一。(2)在矫直过程中浪形区域会同时向板宽方向和板长方向延展而产生压缩变形,板材矫直过程主要是纵向纤维的变化,进而改善板材纵向残余应力,对横向残余应力的改善较小,导致中浪板材矫直后其横向残余应力大于纵向残余应力。浪形特征对浪形区域附近的纵向应力有影响,对横向应力影响不大。(3)通过有限元建模研究矫直过程的应力应变演化,研究不同弯辊量与压下量对矫后板材应力和延伸的影响,得到负弯辊矫后板材会呈现中间小两边大的应力趋势,且随着弯辊量的增加板材边部与中部延伸量差值逐渐增大。
[Abstract]:With the rapid development of home appliances, national defense, aerospace and other industries, especially the rapid progress of China's car industry, the market demand for thin plate and strip is more and more, and the quality requirement is becoming higher and higher. For the plate and strip with wave shape, when it passes through the roller straightening machine, the wave shape will be continuously stretched and compressed, and the residual stress in the plate and strip will be loaded and unloaded continuously, thus achieving the effect of straightening the wave shape and distributing the residual stress evenly. At present, there is no perfect systematic theory on the straightening of the inexpandable plate defects such as medium wave, edge wave, etc. Especially, the defects of thin sheet and strip are complicated, so it is more difficult to study the straightening model and technology. In order to get the straightening rule of wave shape, this paper selects the middle wave to carry on the pertinence research. Considering the limitation of practical conditions, the mid-wave is simplified in the study, and the single mid-wave on a plate is taken to study, and the mid-wave is regarded as the local deformation of the plate, which is convenient for making the desired wave shape effect. In the experiment, the three parameters of wave height, wave width and wave length are defined according to the characteristics of the middle wave, and the wave shapes of different parameters are compared. Some conclusions are obtained as follows: (1) through straightening comparison, it can be concluded that wave height and wavelength have great influence on the straightening effect of wave shape, the higher the wave height, the greater the difficulty of straightening. For waves that are too high, a continuous mini-wave is formed in the original wave area after straightening. The wavelength is approximately 1/2 of the roll distance of the straightening machine. (2) in the process of straightening, the wave region will expand to the width direction and the length direction of the plate at the same time, resulting in compression deformation, and the process of plate straightening is mainly the change of longitudinal fiber. Then the longitudinal residual stress is improved, and the transverse residual stress is slightly improved, which leads to the transverse residual stress being greater than the longitudinal residual stress after the plate is straightened. The characteristics of wave shape have an effect on the longitudinal stress near the wave region, but not on the transverse stress. (3) the evolution of stress and strain in straightening process is studied by finite element modeling, and the effects of different bending roll and reduction on the stress and extension of straightening plate are studied. The results show that the plate will show a large stress trend after the negative bending roll straightening, and the difference between the edge and the middle extension will increase gradually with the increase of the roll bending volume.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG335.5

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