DP600管材充液压形回弹规律研究

发布时间：2019-03-11 20:37

【摘要】：汽车工业、航空航天工业作为高端制造业和先进技术制造的代表,对制造技术的要求越来越高,形状结构复杂、性能要求极高、一体化成形、结构轻量化设计的薄壁管件需求越来越多,此类零件的制造多采用传统冲压和焊接工艺。随着技术的进步和传统拼焊技术缺点的显现,在此背景下充液压形技术发展了内高压成形技术的优势,克服了内高压成形技术的缺点,成为制造薄壁管件技术的研究热点;然而大尺寸薄壁管件、精密薄壁管件对成形精度和装配性能的要求较高,管材充液压形回弹的研究具有一定的意义。本文以DP600高强钢管为坯料进行管材充液压形的回弹规律研究。首先,通过理论分析揭示了内压、圆角半径、壁厚对管材充液压形回弹的影响规律及机理,并给出了内压、圆角半径、壁厚和回弹量、环向力、弯矩之间的数学表达式;其次,利用有限元模拟分析给出了内压、圆角半径、壁厚对回弹量、环向力和弯矩的影响规律,验证了理论分析的正确性,并给出了内压、圆角半径、壁厚对管材充液压形回弹变形轮廓的影响规律;最后,基于理论分析和有限元模拟结果设计实验进行实验研究,实验结果较好地吻合了理论分析和有限元模拟结果,为控制管材充液压形的回弹提供一定的参考。研究结果表明:管材充液压形的回弹随着内压的增大呈现出先增大后减小的规律,回弹最大时的内压为回弹临界内压;管材充液压形的回弹随着圆角半径的增大而减小;另外,圆角半径决定着回弹临界内压的大小,圆角半径越大,回弹临界内压越小,这表明圆角半径和内压对管材充液压形回弹的影响是相互耦合的;壁厚对管材充液压形的回弹的影响受到内压的影响,内压决定着壁厚对管材充液压形回弹影响的规律性。内压、圆角半径对管材充液压形回弹的影响机理是通过改变管材充液压形时环向力和弯矩的大小和方向,进而使管材以拉弯、压弯、纯弯等不同类型的变形形式进行变形;壁厚通过改变管材充液压形时的受力状态和惯性矩来影响回弹。最后,根据研究结果并结合管材充液压形成形工艺和零件的设计给出了控制回弹大小的方法,通过适度控制内压的加载、管材壁厚的选择以及零件圆角半径大小的设计控制回弹。
[Abstract]:As the representative of high-end manufacturing and advanced technology manufacturing, automotive industry and aerospace industry have higher and higher requirements for manufacturing technology, complex shape and structure, extremely high performance requirements, and integrated forming. There is more and more demand for thin-walled pipe fittings with lightweight structure design. Traditional stamping and welding processes are used in the manufacture of this kind of parts. With the progress of the technology and the appearance of the shortcomings of the traditional splice welding technology, the filling hydraulic forming technology has developed the advantages of the internal high pressure forming technology under this background, overcome the shortcomings of the internal high pressure forming technology, and has become a research hotspot in the manufacture of thin-walled pipe fittings. However, large-size thin-walled pipes and precision thin-walled fittings require higher forming accuracy and assembly performance, so the research on hydraulic shape springback of pipes is of great significance. In this paper, DP600 high-strength steel pipe is used as billet to study the springback law of hydraulic shape of pipe. Firstly, the influence and mechanism of internal pressure, radius of fillet and wall thickness on hydraulic springback of pipe are revealed by theoretical analysis, and the mathematical expressions of internal pressure, radius of fillet, wall thickness and springback quantity, circumferential force and bending moment are given. Secondly, the effects of internal pressure, radius of fillet and wall thickness on springback, circumferential force and bending moment are given by finite element simulation analysis, the correctness of theoretical analysis is verified, and the internal pressure and radius of fillet are given. The effect of wall thickness on the springback profile of pipe filled with hydraulic pressure; Finally, experimental research is carried out based on theoretical analysis and finite element simulation results. The experimental results are in good agreement with the theoretical analysis and finite element simulation results, which provide some reference for controlling the springback of pipe filling hydraulic shape. The results show that with the increase of internal pressure, the springback of hydraulic-filled pipe first increases and then decreases, the internal pressure of the maximum springback is critical internal pressure of rebound, the springback of hydraulic-filled pipe decreases with the increase of the radius of the fillet, and the springback of the hydraulic-filled tube decreases with the increase of the radius of the fillet. In addition, the radius of the fillet determines the critical internal pressure of springback, and the larger the radius of the fillet, the smaller the critical internal pressure of springback, which indicates that the effect of the radius of the fillet and the internal pressure on the springback of the tube filled with hydraulic pressure is coupled; The effect of wall thickness on the springback of hydraulic shape is affected by the internal pressure, which determines the regularity of the effect of wall thickness on the springback of the hydraulic shape of pipe filling. The mechanism of the influence of internal pressure and radius of fillet on hydraulic shape springback of pipe is that by changing the size and direction of circumferential force and bending moment, the pipe can be deformed in different deformation forms such as tension bending, compression bending, pure bending and so on. The wall thickness affects the springback by changing the force state and moment of inertia of the tube when the hydraulic profile is filled. Finally, according to the research results and combined with the hydraulic forming process of pipe filling and the design of parts, the method of controlling the springback size is given, and the loading of internal pressure is controlled appropriately. The selection of tube wall thickness and the design of fillet radius control springback.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG394

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