ANSYS analysis of the distribution of the part stress of the blade during the shearing process
The cutting edge of a shearing machine is influenced not only by shear force, extrusion pressure and friction, but also by high temperature of steel billet during the shearing process. Blooming plant bloom temperature is generally in the 800 ~1000C, so high temperature will cause long-term effect on the cutting edge, thus speeding up the soft tool wear knife, blade repair problem has attracted many experts attention, blade repair has become a research topic on the experts. In practice, many manufacturers and units try to solve the collapse knife, but because of the special environment at the scene, people can not measure the stress state of the blade. So how to solve the problem of blade and blade repair has become a major problem in engineering.
However, with the development of computer technology and computation method, numerical computation method of discretization can be adopted for complex engineering problems, and numerical solutions satisfying engineering requirements can be obtained by computer. In the field of engineering, the most widely used numerical simulation method is the finite element method. In many finite element software, ANSYS is one of the best software, it can solve complex engineering problems and simulate its stress state. In order to find out the cause of collapsing force and provide 1 basic conditions for blade repair, the material of the shearer blade is 5CrW2Si, and the hardness at room temperature is about 45HRC after heat treatment, and its structural form is the whole structure. In the conventional strength checking design, the material meets the strength requirement, so the strength condition is not the cause of the failure of the cutting tool.
4node182 was 1, the static strength analysis, elastic modulus of 196GPa friction coefficient 0.1. 2 by solid model analysis of shear blade loads such as.
The maximum shear stress Pmax T thrust F friction by the following formula can calculate the maximum shear stress model of Pmax. entity graph Fmax is a rolling shear load original section area of the largest mm Tax cut workpiece material corresponding shear temperature the maximum shear resistance of MPa K unit is considered from the blade blunt blade gap increases to improve the coefficient of shear force, shear capacity is calculated according to the selected: Liu Xiaogang / the empirical data; Y= Table 2 lateral thrust plate shear. The numerical blade angle of friction Y lateral thrust T (T) vertical friction force F (T) 5160. usually is pressed to calculate the maximum shear force.
The maximum shear stress shear for =150MPa high carbon steel during shear strength was C rolling material in the corresponding shear temperature: scissors body bear pressure: according to the e=z/h=0. shear stress maximum blade indentation depth: 3 finite element analysis condition of unit 108, 133 nodes; node displacement constraints 26. Node pressure 2, unit 2 plane loads. The active coordinate system is a plane coordinate system, and the analysis option takes into account the large deformation effect.
The shear machine is subjected to the maximum shear force on the cutting edge and the friction caused by sliding during the shear process. The maximum shear force across the blade on the knife surface, the width of the assumption of 90mm. shear stress angle from 5 to 10 workpiece contact surface on the workpiece and cutter length greater than the knife is uniform, the lateral pressure is uniform, lateral friction force direction Y negative, X positive horizontal friction force direction, in order to the convenience of discussion, the assumption of zero.
At the same time, the stress value of the stress concentration point is different at the same time, and the change curve is shown. It can be seen from the diagram that the stress values change little.
Under different loading conditions, as shown, the maximum point of tensile stress is the curve of the change of the blade. The range of change is between 16~13 centimeters.
Under different loading conditions, the stress distribution of the maximum stress shear blade varies with the rolling angle of the rolled piece, that is, the change of tensile stress and compressive stress distribution as the loading condition changes, as shown.
The stress state of the blade of the shear blade can be approximately described as the form shown.
It can be seen from the point that the side of the cutting edge of the cutting edge presents the stress zone on the side of the tensile stress region. The maximum stress point of the tensile stress area can be found, as shown, but the position of the maximum point changes with the different loading, as shown. The material under normal circumstances because of the heat treatment and processing aspects of the appearance of micro cracks, although the upper part of the blade stress relative to the yield limit of material is small, but in the repair of some elements in the surfacing materials such as W on the thermal sensitivity of strong, often resulting in shear stress in the process of shedding the maximum crack propagation until the blade part of material this is the cause of collapse, knife. It has been proved that the cutting edge of the scissors often occurs at the point of 15mm from the tip of the knife. 4 (1) at the shear site, the cause of the phenomenon of the collapse is due to the stress concentration caused by the crack expansion. In order to avoid this phenomenon, the tool should not be used as a whole, and different materials are used in different stress areas.
In the process of repair, the cutting edge of the blade, such as the A area in which the toughness or tensile properties are better, is surfacing.
On the side of the blade, there is a B in the stress area, which is in the side. When the blade is repaired, it should be surfacing with the material of hard, wear-resistant and high compressive strength. This method can save precious metals and improve the utilization of materials.