Giant Forging Press, A Typical Combination Of Load-bearing Structures Interference Join The Interface Of Research And Optimization,

Large-scale die forging hydraulic press mainly used to forge the heavy forgings, is the key equipment in manufacturing of large aircraft. Meanwhile, it is also the important equipment in the areas of aerospace, shipbuilding, heavy equipment, and so on. The ability to built such machine is a significant symbol indicating the production capacity, technical level of heavy equipments, the economy and national defense strength of a county. The structure of large-scale die forging hydraulic press is giant and complex, the traditional integral structure can not be adopted. For example, the developing 800MN die forging hydraulic press, whose main frame is the C-shaped frame structure, and the different components of such large-scale die forging hydraulic press are connected by prestressing tie-rod, hinge joint, welding, interference fits to constitute the overall structure in the form of series or parallel. The contact state of the different bearing components is the important factors which effect the large-scale die forging hydraulic press's reliability and service life, and the reliable connection between bearing parts and connecting components is the foundation to ensure the good contact among components.The typical composite structure (interference fits) of 800MN die forging press was taken into account in this dissertation. And the interference fits was researched systemically by means of theoretic analysis, experimental research and numerical simulation. The main research work are as follows:(1) The whole structure of 800MN die forging press was analyzed to identify the transfer law of force flow between different supporting parts, and experiment tests were carried out and verified the key link (C plates and cross key) which effects the uniform of force flow between the supporting components of the C-shaped frame.(2) The finite element model of typical structure (C plates and cross key) was built by Global-Local technique in the base of the whole structure's analysis. The stress was analyzed under the extreme loading, the slot and uneven distribution of contact stress were found out between C plates and cross key. (3) The local stress analysis of the interference fitsbetween C plates and cross key was carried out. Four different methods based on the principle of rigidity matching relationship of the compose supporting structure and static equilibrium principle, were proposed to improve the contact status between C plates and cross key through the FEA and mechanical analysis. The best method which makes the force flow uniform was determined.(4)The methods to calculate amount of interference in traditional hub structure had been analyzed. On account of the characteristics of interference fits, the graphic method which is a simple and feasible way to solve the amount of interference on the non-traditional structure is proposed. Then the optimum magnitude for the structure of C plates and cross key was obtained. The interference fits between C plates and cross key with different magnitudes of interference had been analyzed, and the feasibility of graphical method which was established for solving the optimum magnitude of interference on the non-traditional structure has been verified.