| 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.
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