Papers by Keyword: Plastic Bending

Abstract: The main goal of the investigation is to determine key technological parameters, necessary for producing required curvature of sheets up to 4000 mm in width with the required mechanical properties. Investigation into dynamics of the process' main technological parameters allowed it to define its three characteristic stages: asymmetric rolling, asymmetric rolling in combination with initial unsettled plastic bending, and asymmetric rolling combined with settled plastic bending. It was found out that the intensity of the deformations changes unevenly, depending on the height of the deformation zone, on all three stages, with its highest value being in the lower part of the sheet, and with the lowest value being in its center. In the second stage, the intensity of the deformation abruptly increases, and a significant asymmetry on the sheet thickness occurs. In the third stage, the non-uniformity of the intensity deformations fields decreases. Similar results can be also observed for stress intensities. Casings on two converters were produced and installed in the oxygen-converter plant.

Abstract: The finite difference method is applied to derive approximate solutions for the elasto-plastic bending of Euler-Bernoulli beam problems. The investigations are restricted to a simple exemplary configuration, i.e. a straight cantilevered beam with constant rectangular cross-section and linear-elastic/ideal-plastic material properties, loaded by a constant distributed load. Only finite difference approximations of second-order accuracy are considered and special emphasis is given to the influence of the load step, the number of layers, and the number of nodes. Based on comparisons with the analytical solution, clear recommendations can be given on the required parameters to obtain a certain accuracy in the numerical approach.

Abstract: In this paper, the effects of the thicknesses of sheet and adhesive layer on plastic forming of adhesively bonded sheet metals were investigated by experiments and the corresponding numerical simulation. The main conclusions obtained are as follows: (1) When the thickness of the adherends increases, the gull-wing bend of the bent sheet and the transverse shear deformation in the adhesive layer become larger, which in some cases the delamination occurs in the adhesive layer. (2) The gull-wing bend of the bent sheet becomes larger with increasing adhesive layer thickness, but conversely the shear strain in the adhesive layer becomes smaller.

Abstract: The article focuses at technology development of the vertical asymmetric rolling and combined process of vertical asymmetric rolling and plastic bending. It has been shown that vertical asymmetric rolling peculiarity relates to the presence of a mixed zone, in which friction forces on contact roll surfaces are directed are differently. Experimental research showed serious drawbacks in the rolling technology caused by the growth of dynamic loads arising at the moment of plate contact with the bending roller. For solving the problem it was proposed to make the roller position motile to allow its movement along the required trajectory. The application of the motile roller helps to reduce dangerous torque differentiation at working rolls by the value of 1,5-2,5 compared with the rigidly fixed roller. The most effective bending roller trajectory is a second-order curve that is convex parabola.

Abstract: The paper deals with numerical analysis of the process of roller leveling of long products. The problem of multiple elastic plastic bending is solved by a program in Matlab, which is based on the Finite Element Method. The aim is to provide a simple, user friendly tool, capable of quick and reliable analysis of the process without the necessity to work with large multipurpose FEM packages. Direct solution of the problem is formulated, starting from the roll intermeshing and product geometry. Roller loading, product deflection, curvature and plastification are the output parameters of the program. With fast and reliable solution of the direct problem, optimal setting of the leveling process will be sought in an iterative process.