薄壁槽钢零件辊弯成形数值模拟及其边波缺陷研究

发布时间：2018-02-13 14:11

本文关键词： 薄壁槽钢零件辊弯成形边波波动量有限元数值模拟　出处：《湘潭大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,冷弯型钢产品类型逐渐向薄壁、轻量化、高强度、复杂断面等方向发展,而薄壁冷弯型钢零件辊弯成形时更容易产生边波等缺陷,严重影响产品外观和使用性能。尽管辊弯成形技术在国内外得到了极大的发展,但是其成形理论仍然不够系统,实际生产中亦只能依靠经验进行轧辊设计和工艺调整。因此,研究薄壁冷弯型钢零件辊弯成形过程及其成形缺陷具有重要的意义。本文利用ABAQUS有限元软件对薄壁槽钢零件辊弯成形过程进行有限元模拟,揭示了薄壁槽钢零件在辊弯成形过程中的金属变形规律和特点,分析了薄壁槽钢零件辊弯成形过程中边波(边缘波浪)的成形的机理,设计了一个边缘波动量的评估标准Δy,并以波动量Δy为评估参数,设计了边波影响因素的正交模拟实验,分析了零件材料的屈服强度σs、辊弯成形道次n、零件翼缘高度h、材料厚度t等因素对辊弯成形边波波动量Δy的影响,主要结论如下:1)薄壁槽钢零件辊弯成形过程中,较大的应力应变主要集中在弯角部位,应力应变大小随着弯曲角度的增加(即道次序数的增加)而增加,而应变分布比应力分布较均匀。在逐步折弯过程中,材料在宽度方向上被拉长,相应地在长度方向上缩短、厚度方向变薄,且横向(宽度方向)应变值远大于纵向及厚向应变值。2)边波产生的机理是由于零件翼缘部位各点产生了纵向应力和不可恢复的纵向塑性应变、且其大小沿翼缘长度方向(纵向)及高度方向分布不均匀引起的:分布不均的纵向应力在翼缘边部产生弯矩,在纵向拉应力处产生纵向塑性伸长,翼缘边部向外侧倾斜;在纵向压应力处产生纵向塑性压缩,边部向内侧倾斜。3)板料的屈服强度σs、成形道次n、翼缘高度h以及板料厚度t等因素均会影响边波的产生和波动量的大小,对边波波动量Δy的影响程度为htσsn。4)边波波动量Δy随着材料屈服强度σs和板料厚度t的增大而减小;随着翼缘高度h的增加而显著增大;随成形道次n的增加,Δy先减小后增大。5)在设计薄壁槽钢零件时,为避免成形时产生边波,应尽可能减小翼缘高度并选用屈服强度较高的材料;在设计薄壁槽钢零件辊弯成形工艺时,应选择合理的成形道次并采取润滑、增加整形工序等工艺措施来控制边波的波动量。
[Abstract]:In recent years, the product types of cold-formed steel have gradually developed towards thin-walled, lightweight, high-strength and complex cross-sections, while the defects such as side waves are more easily produced in the roll forming of thin-walled cold-formed steel parts. Although roll bending technology has been developed greatly at home and abroad, its forming theory is still not systematic enough, and it can only rely on experience to design and adjust the roll in practice. It is of great significance to study the roll forming process and its forming defects of thin-walled cold-formed steel parts. In this paper, ABAQUS finite element software is used to simulate the roll bending process of thin-walled channel steel parts. The metal deformation law and characteristics of thin-walled channel steel parts in roll bending process are revealed. The forming mechanism of edge wave (edge wave) in roll bending forming of thin-walled channel steel parts is analyzed. An evaluation criterion of edge fluctuation 螖 y is designed, and the orthogonal simulation experiment of the influence factors of edge wave is designed with the fluctuation 螖 y as the evaluation parameter. The effects of yield strength 蟽 s, roll bending pass number n, flange height h and material thickness t on the wave momentum 螖 y at the edge of roll bending forming are analyzed. The main conclusions are as follows: 1) in the process of roll bending forming of thin-walled channel steel parts, The larger stress and strain are mainly concentrated in the corner, the magnitude of stress and strain increase with the increase of bending angle (that is, the number of trace sequence), and the distribution of strain is more uniform than that of stress. The material is elongated in the width direction, shortened in the length direction, thinned in the thickness direction, The mechanism of the lateral (width direction) strain value is much larger than the longitudinal and thick strain value. 2) the mechanism is that the longitudinal stress and the unrecoverable longitudinal plastic strain are produced at each point of the flange of the part. And its size along the flange length direction (longitudinal) and height direction distribution is not uniform: uneven distribution of longitudinal stress in the flange edge of bending moment, in the longitudinal tensile stress caused by longitudinal plastic elongation, flange edge edge to the lateral tilt; Longitudinal plastic compression occurs at the longitudinal compression stress, and the yield strength 蟽 s of the sheet is inclined to the inner side, the forming pass is nn, the height of the flange h and the thickness of the sheet metal t all affect the generation of the side wave and the magnitude of the fluctuation. The influence degree of wave momentum 螖 y on the edge wave is ht 蟽 n. 4) the wave momentum 螖 y decreases with the increase of material yield strength 蟽 s and sheet thickness t, and increases significantly with the increase of flange height h. When designing thin-walled channel steel parts, the flange height should be reduced as much as possible and the material with higher yield strength should be selected in order to avoid the edge wave in the design of thin-walled channel steel parts. When designing the roll bending forming process of thin-walled channel steel parts, it is necessary to select reasonable forming passes and take some technological measures such as lubrication and increasing shaping procedure to control the fluctuation of side wave.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

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