CT20钛合金薄壁管材数控冷弯成形行为研究

薄壁管材的小弯曲半径数控弯曲成形十分困难,外侧壁厚减薄是弯管成形中的加工缺陷之一,对于钛合金薄壁管尤为严重。采用模拟与实验相结合的方法,对规格为58 mm×1.5 mm的CT20钛合金管材数控弯曲成形过程中弯曲段的壁厚减薄进行了研究,得到相对弯曲半径对壁厚减薄的影响规律。结果表明,CT20钛合金管材冷弯成形时的极限相对弯曲半径(R/D)为2。     

铝合金小弯曲半径薄壁管数控绕弯模具设计

铝合金小弯曲半径薄壁管数控绕弯成形是多模具约束、多因素影响的复杂成形过程,成形过程中极易出现起皱、破裂等成形缺陷,而模具材料和结构的合理设计对成形质量的影响至关重要。通过分析铝合金小弯曲半径薄壁管的结构特点,结合导管数控绕弯工艺过程,对模具材料选取、模具结构设计及成形仿真等关键技术问题进行了研究,最终确定了铝合金小弯曲半径薄壁管数控绕弯模具的材料、结构形式、尺寸参数,通过数控绕弯成形几何运动仿真、有限元数值模拟与工艺实验,实现了满足设计要求的铝合金小弯曲半径薄壁管数控绕弯成形,证明了小弯曲半径薄壁管数控绕弯模具的可行性,为工程化应用奠定了基础。     

基于Python的ABAQUS后处理研究开发及其在薄壁管数控弯曲中的应用

为了提高对非线性有限元软件ABAQUS结果提取及分析的效率和精度,基于面向对象的Python语言,对ABAQUS后处理程序进行了研究开发。提出了程序开发的思路及一般步骤,并基于此,研究开发了针对薄壁管数控弯曲这一具体应用的ABAQUS后处理程序,用于薄壁管弯曲起皱的判断和起皱区域的确定,以及最大壁厚减薄量的计算和其所在位置的确定,为实现弯管数控弯曲这一复杂成形过程的优化奠定基础。结果表明,所开发的程序能够从ABAQUS海量的计算结果中有效、精确地提取有用信息并进行操作,从而实现对模拟结果的定量分析和总结。文章也为基于Python的研究开发在其他领域的应用,提供了重要指导与借鉴。     

数控弯管仿真系统的设计与开发

管料的数控弯曲是一种先进的管弯曲塑性加工技术，而数控弯管技术的高效应用需要相关的软件支持。本文设计与开发了数控弯管仿真系统（NCTBS系统），基于数据库技术实现数控弯管CAD/CAPP/CAE技术的集成，旨在建立适用的工艺数据库，提高数控弯管工艺水平。     

薄壁管数控弯曲截面畸变的实验研究

截面畸变是薄壁管小弯曲半径数控弯曲成形容易出现的成形缺陷之一。文章采用实验法,研究了芯头个数、芯棒伸出量、弯曲角度、压块润滑状态、相对弯曲半径、材料等因素对截面畸变的影响;并提出了减小截面畸变的有效措施。结果表明,增加芯头个数与芯棒伸长量都能减小弯管的截面畸变,但两者都导致弯管壁厚减薄量增大;随着弯曲角度的增加,截面畸变越严重,相对弯曲半径越小,无芯棒与芯头支撑段弯管的截面畸变愈严重;在压块无润滑情况下,弯管的截面畸变和壁厚减薄量都小,并且在同等弯曲条件下,1Cr18Ni9Ti弯管的截面畸变小于LF2M弯管。     

基于关系数据库的数控弯管成形有限元仿真管理系统研究与开发

采用计算机建模仿真与理论及实验研究有机结合的方法,对复杂的数控弯管成形过程进行研究是一种可行和可靠的手段。数控弯管仿真及实验过程涉及大量数据、模型和结果,为对这些信息进行存储和管理,以及将研究中积累的宝贵知识进行共享和重用,从而提高数控弯管成形过程有限元仿真和实际生产的效率和精度,文章基于关系数据库技术,研究开发了数控弯管成形有限元仿真管理系统。结果表明,该系统不仅能指导研究工作者进行高效精确的数控弯管数值模拟研究,而且能全程指导实验研究及实际生产,并且能迅速有效地将专家建议提供给操作人员。     

数控弯管成形工艺管理系统设计与开发

在数控弯管工艺的理论研究、模拟研究和实验研究的基础上,结合实际生产的经验和需求,设计与开发了数控弯管成形工艺管理系统。该系统实现了数控弯管成形过程工艺数据的有效管理和共享,为实现数控弯管精确成形过程的数字化、工艺自动化作了准备。     

常见弯管缺陷及措施

针对薄壁管弯曲过程中常见缺陷，如金属堆积、金属错层、弯曲凹坑、断裂、丘凸、压痕、皱褶、擦伤等，对弯管模具、管子材料、弯管技术参数和弯管设备等因素进行分析，提出相应的解决措施。     

铝合金大口径薄壁管数控弯曲实验研究

铝合金大口径薄壁管小弯曲半径数控弯曲成形过程中更容易发生起皱、截面畸变和壁厚减薄等缺陷。文章根据成形缺陷产生的原因对弯管模具结构和设备装置进行了改进,包括模具内锁设计、紧凑型柔性芯棒、模具并紧杆和长内衬顶推。在此基础上,采用实验研究方法,对Φ70mm×1.5mm×105mm(外径×壁厚×弯曲半径)的大口径薄壁铝合金管数控弯曲成形质量及应变规律进行了分析,并研究了顶推装置在大口径薄壁铝合金管数控弯曲成形中的效用。     

导管数控弯曲自动编程技术研究与系统开发

数控弯管加工是实现导管数字化集成制造的关键环节,数控编程是进行数控弯管的前提。在研究基于导管三维模型的零件信息提取、数控加工参数计算与补偿和数控编程等技术基础上,自行开发面向不同数控系统的导管数控弯曲自动编程系统,并在某新卫星的导管生产中得到了应用。     

Springback of thin-walled tube NC precision bending and its numerical simulation

The springback is one of the key factors which affect the forming quality of thin-walled tube NC precision bending. The elastic-plastic finite element method was proposed to study the springback process of thin-walled tube NC precision bending and the combination of dynamic explicit algorithm and the static implicit algorithm was proposed to solve the whole process of thin-walled tube NC precision bending. Then, the 3D elastic-plastic finite element model was established based on the DYNAFORM platform, and the model was verified to be reasonable. At last, the springback rule of thin-walled tube NC precision bending and the effect of geometry and material parameters on the springback rule of thin-walled tube NC precision bending were studied, which is useful to controlling the springback of thin-walled tube NC precision bending, and the numerical simulation method can be used to study other effect of parameters on the forming quality of thin-walled tube NC precision bending.     

Effect of mandrel on cross section quality of thin-walled tube numerical controlled bending

The effect of mandrel with the structure of ball and socket on the cross section quality of thin-walled tube numerical controlled （NC） bending was studied by numerical simulation method, combined with theoretical analysis and experiment. Influencing factors of the mandrel include the count of mandrel heads, the diameter of mandrel and its position. According to the principle of NC tube bending, quality defects possibly produced in thinwalled tube NC bending process were analyzed and two parameters were proposed in order to describe the cross section quality of thin-walled tube NC bending. According to the geometrical dimension of tube and dies, the range of mandrel protrusion was derived. The finite element model of thin-walled tube NC bending was established based on the DYNAFORM platform, and key technological problems were solved. The model was verified by experiment. The effect of the number of mandrel heads, the diameter of mandrel and the protrusion length of mandrel on the cross section quality of thin-walled tube NC bending was revealed and how to choose mandrel parameters was presented.     

Effects of process parameters on numerical control bending process for large diameter thin-walled aluminum alloy tubes

Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.     

Effect of frictions on cross section quality of thin-walled tube NC bending

1 Introduction Thin-walled tube bending parts have been increasingly used in many industry fields such as aviation, aerospace and automobile for their easy satisfaction in light weight, high strength and low consuming. The numerical controlled(NC) rotar…     

助推作用对大口径铝合金薄壁管数控弯曲壁厚减薄和回弹的影响

以有限元软件Dynaform为平台,建立了大口径薄壁管数控弯曲及回弹的有限元模型,分析了压块助推速度和压块与管子之间的摩擦系数对壁厚减薄和回弹角的影响规律。结果表明,压块与管子之间没有摩擦或者压块的助推速度为0.9、助推速度为1.0且压块和管子间摩擦系数为0.1的条件下,管子壁厚减薄超过航空标准中允许的最大减薄量0.4375mm。在压块的助推速度不变的条件下,压块与管子之间摩擦系数从0.1增加到0.3,能够有效地降低管外侧的壁厚减薄,但是回弹角也会明显增大。当压块与管子之间的摩擦系数为定值时,助推速度从1.0增加到1.2,对管外侧壁厚减薄的改善作用不大,回弹角没有明显变化。     

薄壁矩形管弯曲过程截面畸变的三维有限元分析

薄壁矩形管的弯曲成形是一个受材料性能和工艺参数等诸多因素交互作用的复杂成形过程,在弯曲过程中极易产生截面畸变等缺陷,导致成形质量难以达到要求。为此,文章提出了薄壁矩形管弯曲成形过程截面畸变的描述方法,并基于ABAQUS/Explicit软件平台,从截面形状变化、截面畸变量大小和弯曲过程中的能量变化等方面,研究了芯棒与管坯间隙和管坯与防皱块之间的摩擦对截面畸变的影响规律。该研究对薄壁矩形管弯曲过程工艺参数的选取,提供了理论依据。