Flat vulcanizing machine is used for vulcanizing flat tapes (such as conveyor belts and belts). It has the advantages of large pressure per unit area of ​​hot plate, reliable equipment operation and simple maintenance. The frame plate is an important part of the frame type vulcanizing machine frame. The rational design of the frame plate directly affects the safety and reliability of the plate vulcanizing machine. In the traditional frame design, the selection of many parameters is simplified by experience and some theories. The design of the components is reasonable to be known through prototyping experiments. Now, the three-dimensional modeling software can be used to design and model the components, and then use the specialty. The finite element analysis software 3D software comes with the analysis module or ANSYS for stress and strain analysis, which shortens the product development cycle, solves the product structure stiffness, strength and other static characteristics and product cost of the contradiction, improve product quality and The purpose of economic benefits.
1 Traditional Design Methods The traditional design and calculation methods are based on material mechanics theory, simplifying the frame plate. The ninth volume of the Handbook of Rubber Industry provides the following calculation methods: simplification of frame plate strength, "deep beam" algorithm for frame plate strength, and experience in design optimization of framed plates. Because in the design often neglects the structure such as the strengthening board, the spigot, the unloading arc, so there is a certain gap between the calculation model and the stress of the real structure, which has certain limitations. At the same time, in order to ensure the strength and stiffness requirements of the frame, the traditional design had to increase the safety factor and reduce the required stress of the material. The actual thickness of the frame plate is much greater than the required thickness, resulting in unnecessary material waste.
The finite element can accurately calculate the stress and strain at each node. The strength and stiffness of the dangerous part of the part can be reinforced by the finite element calculation results. The thickness of the material can be reduced appropriately for the part with small force, so as to save material. Reduce the cost of production.
2 Finite Element Method to Calculate Frame Stress
2.1 The establishment of the model The frame is welded together by a frame plate, a reinforcement plate, side bottom plates, and partition plates. Figure 1 shows the three-dimensional geometric model of the frame. In the area where the stress of the frame plate is concentrated, the reinforcement plate is added, and the reinforcement plate comes from the flame leftover material of the frame plate, which has a good processability. Taking into account the ease of product development and solidworks, pro-e, ug and other three-dimensional solid modeling into the grid after the import of ANSYS may be wrong, so here directly using the finite element analysis module Cosmosworks Solidworks finite element analysis of the framework.
Figure 1 Frame model
2.2 Define Material Properties Material properties are shown in Table 1.
Table 1 Frame Material Properties
2.3 Defining Constraints and Imposing Loads When the flat vulcanizer plate is pressed down, the frame is subjected to the greatest force, while the bottom of the frame is connected to the fastening ground by the anchor bolts. According to the actual stress conditions, the load on the force plate of the frame is the uniform load (Q=11.89 MPa) generated by the maximum force of the hydraulic cylinder, and the bottom of the frame is a fixed constraint.
2.4 Meshing Using free entity meshing, as shown in Figure 2.
Figure 2 Frame meshing
2.5 Solving The Cosmosworks program provides different solutions, direct sparse, FEE, FEEPlus, and FEEPlus solutions. FEEPlus solves large and oversized problems.
3 results analysis
3.1 Stress Analysis The results of the frame stress are shown in Figure 3.
Figure 3 Frame stress distribution
(1) Since the upper part of the frame is subjected to shear force and bending moment, the stress in the inner middle position is the largest and the displayed value is 149.7 MPa.
(2) The corner arc transition of the inner frame of the frame plate better solves the problem of stress concentration.
(3) The lower part of the frame plate, the upper corners of the frame, and the reinforcement plate have less stress. The remaining material left by the cutting steel plate is used for the reinforcing plate, which has good processability and economy.
3.2 Analysis of strain results The strain results are shown in the figure.
Figure 4 Frame strain distribution
The bending deformation of the frame plate caused by the bending moment, the deformation of the frame plate in the middle of the maximum, the maximum value is 2.9mm, the force on both sides gradually decreases, the strain value is also reduced accordingly, this result meets the requirements.
3.3 Checking The distribution of the safety factor is shown in the figure.
Figure 5 Frame Safety Factor Distribution Chart
Flat vulcanizing machine works stably, the impact is small, the frame produces elastic deformation, and the finite element method accurately describes the stress and strain values ​​of each node, and the calculation error is small. Therefore, it is not necessary to ensure the strength and stiffness requirements of the parts without requiring a large safety factor, so the safety factor is chosen to be 1.6.
4 Conclusions Through finite element analysis of the plate vulcanizer frame, the following conclusions have been drawn:
(1) The stress at the corners of the inner frame of the frame plate is the largest, and it should be made into a large radius over-reinforcement and reinforcing plate to reinforce.
(2) On the basis of satisfying the rigidity and strength, the thickness of the steel plate can be reduced, and the remaining material can be used as a reinforcing plate to save the steel and reduce the cost.
(3) Taking the flat vulcanizer frame as an example, this paper describes the basic steps of the finite element analysis of the flat vulcanizer frame and provides a feasible solution for the analysis and calculation of such mechanical products.
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