金属波纹管液压成形工艺优化系统开发

发布时间：2018-06-19 18:52

本文选题：钛合金波纹管 + 液压成形　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：金属波纹管用于制造各种敏感元件、补偿元件、柔性连接件和换热元件,主要应用在航天、航空、汽车、船舶、石油化工等行业,特别在先进航空发动机上,能够填补密封环与轴之间的间隙,大幅度增强结构的密封性能,提高燃料利用率。随着工业技术的不断发展,结构轻量化是一个有效的途径来降低成本和减轻重量,同时可以满足材料的强度和刚度。钛合金质量轻、具有良好的力学性能和抗腐蚀能力成为新型的金属波纹管材料,符合结构轻量化这一发展趋势,在航空、航天、化工等行业有着良好的发展前景。由于钛合金弹性模量小,塑性差,难成形,所以目前在我国的研究和应用较少。本文以弹塑性有限元模型为基础,应用Johnson-Cook塑性本构模型和韧性损伤原理对钛合金波纹管液压成形过程进行仿真分析。建立管材外径为21.5mm、壁厚为0.16mm、成形后最大直径为31.5mm的轴对称有限元模型,模拟管材从初始加载液压到回弹结束的整个过程,将成形过程中的应力应变分布和预测的开裂位置与实际生产进行对比分析,验证有限元模型的合理性。为了防止开裂等缺陷的产生,保证降低最大减薄率和最大损伤变量D的基础上,同时降低回弹量,对模片圆角半径大小、液压大小和模片间距等工艺参数进行优化,得到最佳工艺参数,进而得到相关工艺参数对波纹管液压成形的影响规律。利用优化后的工艺参数得到的成品波纹管回弹量为4.7mm,最大减薄率为32.02%,最大损伤变量D为0.5。根据优化得到的工艺参数,设计并加工的一套波纹管液压成形模具,完成钛合金波纹管的制备。对比实验结果和仿真结果的长度方向上的减薄率,验证有限元分析准确性。实验得到的成品波纹管减薄率大于仿真结果减薄率,波峰最大减薄率处有2%-3%的差异,在管端部有1%-2%的差异,这是由于假设仿真过程中是全部润滑的(摩擦系数0.08),实验过程中未必全部润滑,摩擦系数越大减薄率越大而造成的结果。本文将Abaqus脚本文件参数化编辑利用Qt Designer可视化图文界面,并用Python语言编辑连接语句,将界面与Abaqus连接,完成对Abaqus的自主二次开发,建立优化系统。根据界面的工艺参数、几何参数和有限元参数输入相关数据,即可自动生成CAE文件并完成计算,生成相关结果报告,根据报告来修改工艺参数,快速完成对波纹管液压成形的工艺优化,具有实际意义。
[Abstract]:Metal bellows are used to make various sensitive elements, compensation components, flexible connectors and heat exchange components, which are mainly used in aerospace, aviation, automobile, ship, petrochemical and other industries, especially on Advanced Aero Engines, to fill the gap between the seal ring and the shaft, greatly enhance the sealing performance of the structure and improve the fuel utilization. With the continuous development of industrial technology, the lightweight structure is an effective way to reduce the cost and reduce the weight. At the same time, it can meet the strength and stiffness of the material. The quality of the titanium alloy is light. It has good mechanical properties and corrosion resistance to become a new type of metal corrugated pipe material. Because of the small elastic modulus, poor plasticity and difficult forming of the titanium alloy, the research and application of the titanium alloy are very few in China. In this paper, based on the elastoplastic finite element model, the Johnson-Cook plastic constitutive model and the principle of ductile damage are used to simulate the hydraulic forming process of the titanium alloy bellows. The axial symmetry finite element model with the diameter of 21.5mm, the wall thickness of 0.16mm and the maximum diameter of 31.5mm after forming is established. The whole process of pipe material from initial loading to the end of springback is simulated. The distribution of stress and strain in the forming process and the predicted cracking position are compared with the actual production, and the rationality of the finite element model is verified. In order to prevent the formation of cracks and other defects, to reduce the maximum thinning rate and the maximum damage variable D, and to reduce the springback at the same time, optimize the parameters of the radius of the die fillet, the size of the hydraulic pressure and the spacing of the die pieces, and get the best process parameters, and then the influence of the related process parameters on the hydroforming of the bellows is obtained. The resilience of the finished product bellows is 4.7MM, the maximum thinning rate is 32.02%, the maximum damage variable is 32.02%, the maximum damage variable D is based on the optimized process parameters. A set of corrugated tube hydroforming mould is designed and processed to complete the preparation of the titanium alloy bellows. The thinning rate and the accuracy of the finite element analysis are verified. The thinning rate of the finished product bellows is greater than that of the simulation results. The maximum thinning rate of the wave peak is 2%-3%, and there is a difference of 1%-2% at the end of the tube. This is due to the assumption that all the lubrication (friction coefficient 0.08) is all lubricated in the simulation process, and the friction coefficient is not all in the experimental process. The larger the thinning rate, the result of the larger thinning rate. In this paper, the Abaqus script file parameterized edit is used to visualize the interface of Qt Designer, and edit the connection statement with Python language, connect the interface with Abaqus, complete the independent two development of Abaqus and establish the optimization system. In the related data, the CAE file can be generated automatically and the calculation is completed. The related results report can be generated. The process parameters are modified according to the report, and the process optimization of the bellows hydroforming is completed quickly. It is of practical significance.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG394

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