Papers by Author: Yu Gui Li

Abstract: In this paper, the shear force in the shearing process of the drum type linear blade flying shear is done. Two different approaches were taken to establish the shear force formula, and then the finite element simulation. The comparison results of the calculated values and simulated values can be seen that as the thickness increases, the maximum shear force calculated by the pure shear force formula increases rapidly, the shear force calculated by the energy release rate formula is relatively small, and the finite element simulation values and calculated values close to each other when the plate thickness is small. The derived formula in this paper not only can be applied to complex engineering problems, but also has provided a theoretical basis for drum type linear blade flying shears on the shear force calculations and equipment design.

Abstract: Aiming at the problems existing in the process of shearing such as bad-section quality and low efficiency, several parameters have been changed in experiment research in the text, which is good for the wide application of this shear technology. The results of experiment agree well with shear theory.

Abstract: In the shearing process, these were many problems in shearing, the regularity of metal deformation of shearing was analyzed combined with theory of ductile damage and fracture mechanism of high-speed, the rules of factors which could be affected the shearing was analyzed on the velocity and shearing stress state. These theories would improve the shearing section.

Abstract: ANSYS as finite element software is used to analyze oil film pressure of hydrodynamic oil film bearing, the stress of bearing bush alloy and the simulation movement of shaft and bearing, and then the reasons of oil film bearing failure and the wear mechanism of bearing bush are illustrated in detail.

Abstract: Symmetric valve controlled asymmetric cylinder which is applied to force down system of hydraulic leveler. In this case, the flow metering-in is not equal with metering-out universally in proportional or servo control hydraulic system, "pressure jump" will appear at the time of symmetric valve changing direction[1,2]. To deal with this disadvantage well and improve the system, the disadvantage of symmetric valve controlled asymmetric cylinder is altered by the solution that asymmetric valve controlled asymmetric cylinder. In this paper, the mathematic model of the solution has been worked out actually and the transfer function has been constructed. Finally using simulink software of MATLAB to simulate the system and analyze the stability of closed-loop.

Abstract: The horizontal blade gap is a key problem in rolling shear. The mathematical model is established in this paper. This model is optimized based on traditional model. The optimized formula of blade clearance is obtained and the stress is analyzed in cutting process. It is benefit for improving shear quality.

Abstract: As one of the key devices of finishing line of medium & thick plate, pinch roll is mainly used for clamping, transferring and specialized lengths. Nowadays, there generally exist the off-tracking phenomena of pinch roll apparatus, the shearing and lengthening quality of steel plate are heavily influenced and the normal production of enterprise are disturbed. This paper introduces the micro-scale behaviors of pinch roll apparatus, deeply analyzes the reasons that result in off-tracking of pinch roll, and points out the corresponding solutions, which can provide theoretical guide to the design of new-type pinch roll.

Abstract: No 460 oil-film bearing oil as the dedicated lubricant is regarded as the incompressible Newtonian fluid. To comprehensively analyze the real oil flow state, the mathematical model on velocity profiles, together with its dimensionless equations, is established, and the calculating program is developed to simulate the 3D velocity profiles and velocity gradients at different oil flow layers. The relationship between velocity profiles and the oil film pressure is discussed, and the velocity tendency is consistent with the general velocity profile of wedge cross section. The conclusions are beneficial to the further study on lubricating performances of heavy contact components and to prolong their service lives.

Abstract: According to revised Cailikefu’s rolling shear force formula, motion path equation of spatial seven-bar path is built, and mechanical model, with such new structural features as asymmetric and negative offset, is thus successfully established for 2800 mm heavy shear of some Iron&Steel Company. Shear force and bar force of steel plate, before and after adoption of asymmetric and negative offset structure, are analyzed, as well as horizontal force component of mechanism that influences pure rolling shear and back-wall push force that keeps blade clearance. The discovery is that back-wall push force could be kept large enough at rolling start-up (i.e. the time that the maximum rolling shear produces), meanwhile, back-wall push force is the most approximate to side forces with adoption of 60mm~100mm offset. Theoretical results and on-site shear quality both indicate that new structural features such as asymmetric and negative offset plays an important role in ensuring pure rolling shear and keeping blade clearance constant, which provide an effective means to improve quality of steel plate.