Modeling based on APDL Because the structure of the press is more complicated, the modeling of the ANSYS operating interface is more complicated and inconvenient to modify. The APDL programming language can greatly improve the efficiency of modeling and facilitate modification, and the entire modeling process is also At a glance. In this paper, in order to facilitate the modeling and finite element analysis, the structure of the press is simplified, and some of the upper beams and the base have little influence on the stress and displacement distribution, and some rounded corners are removed. In the modeling process, the main dimensions of each part of the press are first defined to facilitate the replacement of the model size with parameters. Because the structure of the press is connected by studs through the screw holes on the upper beam and the base, this paper uses the bottom-up modeling method to establish the model of the upper beam and then build the model of the base. Finally, a model of the stud is built. The final model diagram, for example, to save space, only intercepts the schematic diagram of the model. The division of the mesh is different due to the different materials and shapes of the various parts of the press. If the whole mesh is automatically meshed, it will inevitably cause some units to be unreasonable. In this paper, the upper beam, the stud and the base are separately. Meshing, then sticking them together without considering missing cells, and encrypting the mesh where certain precision is required. The three-dimensional solid block unit is used to divide the unit into parts, and the contact unit and the pre-tightening unit are used in the part where the stud is in contact with the upper beam and the base, and they are connected and analyzed. Under preload conditions, the most important influence on the brick press is the contact stress. There are two difficulties in the contact problem: one is that the contact or separation between the contact surface surfaces before the problem is solved is unknown, it depends on the boundary conditions of the load material and other factors; the second is that most contact problems must be calculated friction, friction It makes the convergence of the problem difficult. After we have built the model, we must first recognize which parts of the model may touch each other to identify the contact pairs through the specified contact units. Since parametric programming is used in this example, each contact pair can be clearly identified by the number of the specified contact unit. Applying Constraints and Loads Due to the symmetry of the press structure, symmetric constraints are imposed on the yz and xz planes of its structure, applying a fixed constraint along the z-direction of the base. After the constraint is determined, the work is loaded. Under the pre-tightening condition, the press is mainly affected by the pre-tightening force and the surface load, and the surface load is mainly the gravity of each part. In order to allow the analysis to converge when the preload is applied, the displacement used instead of the direct force. Among them, the pre-tightening force is 300t, the upper beam is subjected to force of 250t, and the base is subjected to force of 250t. The results of finite element analysis are calculated by nonlinear analysis of finite element, and the results of stress cloud diagrams of various parts of the press can be obtained. For example, the stress of the press after the finite element analysis can be calculated from the maximum stress of 250 MPa, which occurs in the stud and upper beam. Contact surface. Analyze and compare the conventional method of calculating the contact stress, and calculate the contact stress between the stud and the upper beam and the base by the calculation between the cylinder and the cylindrical concave surface: σmax=0.418PEL×R2-R1R1R23 Known conditions: load P=300N cylindrical radius R1=0.175m cylindrical concave radius R2=0.180m cylindrical contact length l=1.240m elastic modulus E=20600000GPa calculation result: coefficient of contact elliptic equation Ax^2+By^2=C: B=. 08 When the contact body E1=E2=E, μ1=μ2=0.3: contact surface size b=4.140E-07m maximum contact stress σmax=371.78MPa By comparison analysis of the two results, it can be seen that the stress calculation of the traditional method is Neglecting factors such as friction, the results obtained have greater affluence, and the results obtained by finite element calculation are more realistic. The conclusion is based on the brick press model. Based on the APDL model and finite element analysis, the stress distribution of each part of the press under pre-tightening conditions can be clearly obtained. This is the production and manufacture of the press. Guiding significance. Fireplace Stove,Wood Burning Fireplace,Wood Stove Boge Technology (Shanghai) Co., Ltd. , http://www.shportablefireplace.com
Analysis of the tightening touch of the special machine bolts relying on the new control
Modeling based on APDL Because the structure of the press is more complicated, the modeling of the ANSYS operating interface is more complicated and inconvenient to modify. The APDL programming language can greatly improve the efficiency of modeling and facilitate modification, and the entire modeling process is also At a glance. In this article, for ease of modeling and finite element analysis,