摘要 :
The process of soft-punch hydro-forming was use.cl to form some workpieces. However, it has not been completely understood until now. In this paper, based on some primary experiments, in which cups have been tried under different ...
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The process of soft-punch hydro-forming was use.cl to form some workpieces. However, it has not been completely understood until now. In this paper, based on some primary experiments, in which cups have been tried under different working conditions with the soft-punch hydro-forming process, systematical know-how about why the LDR of a metal sheet is different, how working conditions influence qualities of a work-piece,and how the deformation takes place has been achieved when simulations are employed. All these results claim that the cup depth heavily weighs on the cup wall thinning rate, and a satisfied complex part can be achieved when the contacting time between the sheet and the female die is under our control well by a movable slider,which is fixed as the bottom of the female die.
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摘要 :
Sheet metal forming is widely applied to automobile, aviation, space flight, ship, instrument, and appliance industries.In this paper, based on analyzing the shortcoming of general finite element analysis (FEA), the conception of ...
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Sheet metal forming is widely applied to automobile, aviation, space flight, ship, instrument, and appliance industries.In this paper, based on analyzing the shortcoming of general finite element analysis (FEA), the conception of parametric finite element
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With considering the influence of equivalent plastic strain on void-damage and taking Lemaitre damage equivalent stress as plastic potential, based on continuous damage mechanics theory, a new criterion for ductile fracture is der...
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With considering the influence of equivalent plastic strain on void-damage and taking Lemaitre damage equivalent stress as plastic potential, based on continuous damage mechanics theory, a new criterion for ductile fracture is derived. The two key materia
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It is known that some internal defects exist in metal materials. Preliminary attempt to relate dislo cation evolution with metal rheological forming was done. By the attempt, it is learned that the evolution of dislocation density...
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It is known that some internal defects exist in metal materials. Preliminary attempt to relate dislo cation evolution with metal rheological forming was done. By the attempt, it is learned that the evolution of dislocation density p( x, y, t ) is essentially the change of n independent internal variables qα (α = 1, 2, …n ) with material. The preliminary research in theory and experiments showed that dislocations piling-up could be avoided. One can improve the internal microstructure and mechanical properties of products by rheological forming method.
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摘要 :
The forming principle and deformation analysis of NC incremental sheet metal forming process as well as the process planning, experiment and key process parameters of vertical wall square box forming are presented. Because the def...
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The forming principle and deformation analysis of NC incremental sheet metal forming process as well as the process planning, experiment and key process parameters of vertical wall square box forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation, the deformed region of sheet metal thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The forming half-apex angle θ and corner radius R are the main process parameters in NC incremental forming of vertical wall square box. According to sine law, a vertical wall square box can't be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the parallel line type tool path process method is presented to form the vertical wall square box, and the experiment and analysis are made to verify it.
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The forming limits of nickel coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited nickel coating was prepared on steel substrate to f...
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The forming limits of nickel coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited nickel coating was prepared on steel substrate to form advanced structures,and its plastic instability was investigated by the Swift Plastic Instability Theory. By using the compound law for laminated sheet metals, explicit equations for the calculation of the instable eigen values were deduced. The forming limit diagrams of the nickel coating on the right region were plotted. It is exhibited that the forming limit of the coating sheet is between the forming limits of the individual nickel coating and steel substrate. The forming limit of the nickel coating is not so good as that of the steel substrate, and the forming limit strain of the coating sheet tends to diminish with the increase of thickness of the coating. The greater the normal anisotropic coefficient of the materials is, the better the forming limit is.
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Depending upon the polluted features of various mining activities in a typical nonferrous metal mine, the contaminated soil area was divided into four zones which were polluted by tailings, mine drainage, dust deposition in wind a...
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Depending upon the polluted features of various mining activities in a typical nonferrous metal mine, the contaminated soil area was divided into four zones which were polluted by tailings, mine drainage, dust deposition in wind and spreading minerals during vehicle transportation, respectively. In each zone, soil samples were collected. Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods. The results indicate that the average contents of Zn, Pb, Cd, Cu and As in soils are 508.6, 384.8, 7.53, 356 and 44.6 mg/kg, respectively. But the contents of heavy metals in different zone have distinct differences. The proportion of oxidizing association with organic substance is small. Difference of the association of heavy metals is small in different polluted zones.
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