【作者】 仇素萍；

【导师】 彭颖红；

【作者基本信息】 上海交通大学 ， 机械制造及自动化， 2007， 硕士

【摘要】 方形钢管是用途极广和最常见的异型钢管,是一种经济断面管材,与其相同截面积的其他非圆钢管相比,具有重量轻,强度高,抗弯截面模量大,节省金属等优点,以方形钢管等为主要部件的钢结构建筑,不仅容易提高抗自然灾害的能力,也容易对组成部件以及建筑结构进行标准化,被广泛用于建筑、医疗器械、高档家具、汽车、飞机、地铁、造船等行业。目前方形钢管多是以圆管为母管,通过辊弯方式将其断面再次成形为方形,即通过“圆变方”成形工艺制造。本文针对传统四辊封闭式“圆成方”辊弯成形中存在柔性加工能力低、成形推力不足、挤压严重等问题,在分析方管辊弯成形特点及其变形规律的基础上,基于辊弯制造的柔性化设计思想,探索一种方形钢管“圆成方”辊弯成形的新模式——双辊交互式成形模式(Roll-box模式),即对全部或大多数的成形段采用上下轧辊和左右轧辊在沿着钢管前行方向上交互配置的方管生产模式。本文先研究了方管辊弯成形有限元建模的关键技术,建立了Roll-box成形过程的有限元模型。采用动力显式有限元方法对方管辊弯成形过程进行数值模拟计算,分析了管材在双辊驱动模式下应力应变的分布、表面曲率、推力情况、壁厚变化规律及内外表面周向伸缩率的演化规律,详细阐明了Roll-box工艺下的钢管的成形特征。交互配置的轧辊处增厚率是单峰值的,只在终成形段处是双峰值的,有效减低了总增厚率;内外表面的收缩率和拉伸率成对称分布,峰值均出现在管材角部处;内表面角部出现应力集中,且峰值较外表面的应力峰值大。本文还研究了计算参数对计算精度的影响,确定了合理的解析速度和单元划分方案。考虑不同工艺参数对Roll-box成形性能规律的影响,对成形方案进一步优化,以最终确立Roll-box模式仿真模型。更多还原

【Abstract】 As one of most common section steel tubes, square steel tube is widely applied in various industries. Compared with other non- round steel tubes,It have several advantages such as light weight, high strength, material-saving, easiness to installation, etc. It can not only improve capability of resisting nature damage for structures, but also easily standardized in structural industry. So it is used widely in building,medical equipment, top-grade furniture,automobile,plane,subway,ship-building ,etc. Generally, square steel tubes are manufactured by roll forming process by taking round tube as original material, i.e. by a“round to square”forming process.There are some disadvantages in traditional four rolls forming process to produce square steel tubes, such as mode of deformation, flexibility of manufacture, shortage in driving force. After analyzing characteristics and mechanism of square steel tubes roll forming process, a new forming mode, Roll-box, is introduced for square steel tubes forming in this thesis. In Roll-box forming model, the forming horizontal and vertical rollers are set alternately in the longitudinal direction.In this thesis, key technologies of roll-box forming were researched. In order to study the feasibility of the new mode, a large deformation elastic-plastic FEM model is developed by introducing objective constitutive model of rotational formula into the dynamic explicit finite element method.更多还原