Papers by Author: Li Feng Ma

Abstract: The accuracy of the max shear force of rolling shear is of vital importance to the proper selection of motor power and the optimization design of structure strength. The test on shear force during the shearing process of stainless steel was done on 3000 mm cut-to-length rolling shear of some Large-scale Iron & Steel Co., Ltd. The test results have shown that the weight of upper-blade carrier can bring about the fluctuation of measuring signals of shearing force at the start and end instants. Meanwhile, the shear force during the shearing process will gradually increase with the increment relative cut-in depth, and the process from the bite-in of upper blade into steel plate to the fracture of steel plate is very short, thus the link force on the side of firstly-fallen-off blade will initially increase and then will decrease by large increment amplitude. The shear force at the cut-in stage will dramatically increase. During the cut-in stage, the shear force is basically a constant due to the constant shear angle. In summary, the above test results have important referential value to the calculation of shear force and the design of structure strength.

Abstract: A simplified model based on linkage mechanism was set up through analysis of space shear mechanism and kinetic theory of new-type rolling cut double-side shear, complex and matrix has been developed for establishing the kinetic model of linkage mechanism, a novel method for quantitative analysis of rolling-cut double-side shearing was proposed and the efficiency of above mentioned method is illustrated by practical application of kinetic analysis.

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.

Abstract: To solve the three-segment loop-like damage of sleeve under rolling load case, to quantitatively analyze bearing failure mechanism, a mathematical model of oil-film bearing for producing the 3-D contact pressure and shear stress distribution between sleeve and roll neck was developed by 3D elastic contact boundary element method. Some programs for automatically creating 3-D surface grid model have been developed to check data and display deformation, as well as to plot the deformation fields of roller and sleeve. Analytical results provide an effective way to decrease wear and adhesive damage of sleeve, and help to increase the load capacity of oil-film bearing and service life as well.