【作者】 张帅；

【导师】 岳振明；

【作者基本信息】 山东大学 ， 机械工程（专业学位）， 2023， 硕士

【摘要】 金属管材有着轻量化、比强度高、耐腐蚀性强、加工成型性能好等特点和优势,被称之为工业血管,在航空航天、核工业、石油化工、汽车管路、民生管道工程等领域应用十分广泛。这些行业领域为寻求良好的整体结构性能,通常需要一系列的加工方式将管材弯曲成型,使其具有一定的弯曲造型。在管材加工成形过程中,由于传统管材弯曲方式适用范围的局限性,自由弯曲成形技术已经成为材料加工领域的研究热点。该技术可以通过计算机设计软件实时控制弯曲模具的姿态来实现对管材自由弯曲的控制,在加工制造连续变曲率复杂空间构件方面具有较大的技术优势,并且相对于传统的弯曲成形技术,该技术下的成形成本低、效率高、精度高。因此,空间自由弯曲成形技术在工业应用领域具有重要的研究价值与意义。本文以外径20mm,壁厚1.5mm的铝合金管材6061为研究对象,基于三轴式管材自由弯曲成形原理,对管材弯曲成形机理及受力情况进行分析,采用有限元仿真模拟的方法研究分析关键工艺参数对管材成形质量的影响规律,并对自由弯曲成形工艺进行优化,以获得合理的工艺参数取值,进而对空间自由弯曲成形装置进行设计。主要研究内容包括:(1)研究分析自由弯曲成形机理及成形工艺,对管材弯曲过程中弹性和塑性阶段的受力情况及应力应变的分布状态进行描述,并对弯曲过程中中性层的变化规律及壁厚变化进行分析。(2)建立铝合金管材6061的有限元仿真本构模型,开展铝合金管材6061的基础力学实验,通过比对仿真和实验结果,验证仿真本构模型的有效性。(3)基于三轴式管材自由弯曲成形机理,构建有限元仿真分析模型,研究关键工艺参数对管材弯曲成形质量和精度的影响规律,包括:弯曲模移动距离、弯曲模与管材接触处倒角半径、导向机构与弯曲模之间的距离、管材与弯曲模之间的间隙、摩擦系数、管材进给速度等。(4)基于有限元仿真分析结果,通过对自由弯曲成形相关工艺参数进行优化选值,设计并搭建管材自由弯曲成形装置。(5)基于搭建的自由弯曲成形设备,通过逆向识别技术,对管材弯曲特征进行提取分析,建立逆向成形算法和软件操作系统。更多还原

【Abstract】 With characteristics and advantages such as light weight,high specific strength,corrosion resistance and good processing and forming performance,metal pipes are called industrial"blood vessels",which are widely used in aerospace,nuclear industry,petrochemical industry,automotive pipelines,people’s livelihood and other fields.To achieve good overall structural performance,these industries typically require a series of processing methods to bend the pipes into a certain curved shape.Due to the limitations of traditional pipe bending techniques,free bending forming technology has become a research hotspot in the field of materials processing.This technology can control the attitude of the bending die in real time by computer design software to realize the control of free bending of the pipe.It has significant technical advantages in manufacturing continuous-variable-curved complex space components,and compared to traditional bending forming technology,which has lower forming cost,higher efficiency,and higher precision.Therefore,the space free bending forming technology has important research value and significance in the industrial application field.In this paper,the aluminum alloy pipe 6061 with 20 mm outer diameter and 1.5 mm wall thickness is taken as the object of study.Based on the triaxial free bending forming principle of the pipe,the bending forming mechanism and stress situation of the pipe are analyzed.The finite element simulation method is adopted to study and analyze the influence of key process parameters on the forming quality of the pipe,and the free bending forming process is optimized to obtain reasonable process parameter values.Then,the structurure design and development of the space free bending forming device are carried out.The main research contents are as follows:(1)This study analyzed the mechanism and process of free bending forming,described the stress situation and stress-strain distribution in the elastic and plastic stages of the tube bending process,and analyzed the variation law of the neutral layer and wall thickness during the bending process.(2)Establishing a finite element simulation constitutive model for aluminum alloy tube 6061,conducting fundamental mechanical experiments on aluminum alloy tube 6061,and comparing the simulation results with the experimental results to verify the validity of the simulation constitutive model.(3)Based on the three-axis free bending mechanism of tube bending,a finite element simulation analysis model was constructed to study the influence of key process parameters on the bending forming quality and precision of the tube,including the displacement of the bending die,the fillet radius at the contact between the bending die and the tube,the distance between the guide mechanism and the bending die,the gap between the tube and the bending die,the friction coefficient,and the feeding speed of the tube.(4)Based on the results of finite element simulation analysis,the pipe free bending forming device are designed and built by optimizing the values of the process parameters related to free bending forming.(5)Based on the constructed free bending forming equipment,the bending characteristics of the tube are extracted and analyzed through reverse recognition technology,and the reverse forming algorithm and software operating system are established.更多还原