不同加载方式下磁性介质辅助加压板材成形性能研究

发布时间：2018-01-04 03:22

本文关键词：不同加载方式下磁性介质辅助加压板材成形性能研究　出处：《哈尔滨理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科学技术的发展,许多新的智能材料逐渐被发现或制造出来,其中,它们很多已经被应用于工业实际生产之中,产生了巨大的经济和社会效益。在此背景推动下,智能材料的发展为板材柔性介质成形领域注入了新活力,磁性介质是由磁导率较高且磁滞性较低的微纳米级软磁性颗粒、非导磁性液体及添加剂混合而组成的悬浮体。此种磁性介质在零磁场情况下可呈现出牛顿流体的特性,而在磁场作用下能瞬间从液态转化为半固态甚至类固态,值得说明的是磁性介质的此种转变是瞬时可逆的。首先分析研究了智能材料磁性介质的组分、性能特点等,购置了本次研究所需的磁性介质。其次,提出了磁性智能介质性能测试方法,研制了相应的专用工装结构并对介质性能进行了系统的测试分析。结合有限元模拟,给出了励磁凸模直径、通电电流及线圈匝数与磁场分布的关系,优化得出了最佳的工艺方案。本文以304不锈钢板为例,在不同加载方式下,系统研究了磁性介质辅助加压对板材的成形高度、成形极限及壁厚分布等的影响规律。不同磁场作用下,磁性介质的流变特性会随之发生变化,从而导致了板材在成形过程中其受力状态、变形行为的改变。随着电流强度的增加,同等凸模加载量情况下板件的成形高度相应变大,其各部位减薄程度也随之增加,且底角部减薄程度最为严重。随后进行了磁性介质双向加压板材成形工艺实验,研制了背压单元,实现了对板材双侧同步加载的作用。研究结果表明:当电流由0 A增至4 A时板材极限成形高度的增幅达到了18.03%;当凸模加载量为15 mm时壁厚最大减薄率由28%降至22.6%且成形高度有增大趋势变化。可知在增加电流强度后产生的渐强磁场作用下,磁性介质的加载传力效果及粘附作用促进了板件壁厚分布及变形均匀性的改善。随着该工艺的逐渐成熟,有望为板材柔性介质加压成形工艺的研究开辟一条新思路。
[Abstract]:With the development of science and technology, many new intelligent materials have been discovered or created, among them, many of them have been used in industrial production, produced a huge economic and social benefits. This background under the impetus of the development of smart materials has injected new vitality into the medium of sheet metal flexible forming field, magnetic media is made micro nano particles and high permeability soft magnetic hysteresis of the low - magnetic liquid and additive composition. The magnetic suspension medium may exhibit characteristics of Newton fluid in zero magnetic field case, and in the magnetic field can instantly from liquid into semi solid or solid, it is worth the change of magnetic medium is instantaneous reversible. The analysis of smart materials and magnetic media components, performance characteristics, acquisition of magnetic medium in this study required the. Second, the method is presented to test the performance of smart magnetic medium, developed a special structure and corresponding frock on dielectric properties were analyzed. The test system based on the finite element simulation, gives the excitation of punch diameter, through the relationship between electric current and the number of turns of the coil and the magnetic field distribution, optimization to obtain the optimal process scheme in this paper. In the 304 stainless steel plate as an example, under different loading modes, magnetic media assisted pressure forming height on board system to study the influence of forming limit and wall thickness distribution. Under different magnetic fields, the rheological properties of magnetic medium will be changed, which leads to the plate in the process of forming the stress state and the deformation behavior change. With the increase of current intensity, the same punch loading conditions of plate forming height increased, the various parts of thinning degree also increased, and the bottom of the thinning degree Serious. Followed by a magnetic medium of biaxial compression sheet forming process experiment, developed pressure unit, the realization of bilateral synchronous loading sheet. The results show that when the current increased from 0 A to 4 A sheet forming limit height reached 18.03% increase; when the punch load is 15 mm thick wall the maximum thinning rate from 28% to 22.6% and the increasing trend of forming height changes. The crescendo magnetic field produced an increase in the current strength of the magnetic medium, loading force effects and promote the adhesion of the plate wall thickness distribution and deformation uniformity is improved. As the process is expected to gradually mature, flexible sheet the research on the forming process of medium pressure opens up a new idea.

【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB381

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