【作者】 吴生富；

【导师】 聂绍珉； 金淼；

【作者基本信息】 燕山大学 ， 材料加工工程， 2006， 博士

【摘要】 锻造在工业生产中占有举足轻重的地位,是机械制造业的基础工艺之一。伴随着钢铁、汽车、化工、电力、航空航天等行业的迅速发展,锻造在国民经济和国防安全中的作用越来越重要。大锻件的生产能力和质量是衡量一个国家工业发展水平的重要标志之一。大型锻件通常在液压机上锻造,因此,是否拥有大型自由锻造液压机是一个国家大型装备制造能力和技术水平及经济与国防实力的重要标志,具有明确的战略意义。世界各国,无论是发达国家还是发展中国家,都十分重视大型自由锻造液压机的发展。本文综合运用理论分析、数值模拟、人工神经网络、优化和实验测试的多种手段对我国现行自主研制的150MN大型自由锻液压机本体结构中的整体性、导向间隙等关键性问题进行了系统的研究。本文首次将全预紧组合机架用于大型锻造液压机,在整体性分析中,首次提出了考虑横梁变形的“真预紧曲线”,进而提出了临界载荷、整体区、开缝区及分离区等概念。为全预紧机架的整体性分析提供了新的平台。本文以有限元模拟为分析工具,对150MN自由锻液压机本体的整体性进行了分析,提出液压机的整体性主要体现为上梁与立柱结合面处的开缝问题。依据两者间开缝趋势的特点,可将其分为平移性开缝和弯曲性开缝。系统地研究了拉杆、立柱、上梁刚度等结构参数,以及偏载、预紧力等力能参数对压机整体性的影响。并在上述研究的基础上提出了对150MN自由锻水压机本体设计的修改意见,并对最终设计方案进行了全面的分析。本文综合运用人工神经网络、优化和有限元分析技术对150MN锻造液压机组合下梁的整体性进行了研究。通过大量的学习训练,建立了具有很高精度的基于人工神经网络的下梁整体性分析系统。在此基础上深入探讨了各拉紧螺栓直径、预紧力及拉紧板预紧力对下梁整体性的影响。并通过遍历优化给出了最佳的拉紧螺栓直径及预紧力的组合。本文以三维有限元接触计算的方法深入研究了动梁与立柱导向间预置间隙对承载后动梁与立柱间的接触状态影响。探讨了载荷、偏载大小、间隙分布形式、间隙大小对接触状态、动梁转角及面压的影响。并通过热-力耦合分析了温度场对接触状态和接触面压的影响。在此基础上,提出了150MN液压机立柱的预置间隙设置方案。本文制作了150MN锻造液压机的1:7.5金属模型,用电测法对模型压机机架和下梁的整体性,以及承载状态下拉杆和立柱的应力进行了测试。实验结果表明本文通过计算给定的机架及下梁预紧参数可以满足压机的整体性要求,立柱和拉杆的应力与计算结果吻合较好。更多还原

【Abstract】 Forging, as a basic technology in mechanical engineering, is very important inindustries. Along with the rapid development of many other industries, such as steel,automobile, chemical, electricity, aviation and spaceflight industries, the action of forgingbecomes more and more important in national economy and national defense. Theproduction capacity and quality of heavy forgings is one of important symbols to evaluatethe industry level of a country. Because heavy forgings are usually forged on free forginghydraulic press, possessing the machine is also a significant symbol indicating theproduction capacity, technical level of heavy equipments, the economy and nationaldefense strength of a country, having specific strategic significance. Whichever developedcountries or developing countries in the world pay attention to the development of heavyfree forging hydraulic press. This dissertation studies systemically on many key issuessuch as integrity, guiding clearance, etc. of 150MN heavy free forging hydraulic pressdeveloped by China, by means of theoretic analysis, numerical simulation, artificialneural network, optimization and tests.In this dissertation a new type of heavy hydraulic press with whole pre-tighten,assembled frame are presented. Some new concepts such as Real Pre-tighten Curve,Critical Load, Integrated Zone, Gapped Zone and Apart Zone are suggested for the firsttime, offering a new platform for the integrity analysis of the frame. The body integrity ofthe 150MN free forging hydraulic press is analyzed with FEM, and a viewpoint that thefailure of integrity is mainly incarnated by the gapping at the junction of the crossheadand the columns is put forward. The gapping can be divided into translation gapping andbend gapping, depending on the trend of cap developing. Also the effects of the structureparameters of tie-rod, column, crosshead, as well as of the force-energy parameters suchas bias load, pre-tight force, on the integrity are studied systemically. Based on abovestudies, some suggestions for perfecting the designing of the press are put forward, andthen the final designing scheme is whole investigated.In this dissertation, the integrity of the assembled base of the press is also studiedusing artificial neural network method, optimization method and FEM. A high precisionanalysis system for integrity of the base is established based on a great deal of trainingof the artificial neural network. Furthermore the effects of the diameters and pre-tightforces of tightening bolts as well as the pre-tight forces applied by the tightening plates,on the integrity of the base, are thoroughly discussed. The optimal combination ofdiameters and forces of tightening bolts is given out.The effects of the presetting clearance between the moving cross-head and thecolumns on the contact state of them under load are studied by means of 3-D FEMcontact calculation. The effects on the contact state, the tilt angle of and the surfacepressure on the moving cross-head, applied by the load, the load bias, the distribution andthe size of the clearances are researched into deeply. The effect of the temperature field onthe contact state and the contact surface pressure is analyzed by means ofthermo-mechanical coupling. At last, the scheme of presetting clearance about columns isput forward.During the research, a metal model in the proportion of 1:7.5 for the press is build.Measurements and tests about the integrity of the frame and the base of this machine, thestress of tie rod and column under loading are conducted. The results indicate that thepre-tighten parameters of the frame and the base determined by calculation, can meet theintegrity requirement of press, and the stress of pre-tight rod and column obtained fromexperiments well coincide with that from calculation.更多还原