Overview of finite element analysis methods for vibrating screens with vibration sources as vibration motors

Vibrating screens are widely used in the coal and mining industries. When there is not much need for excitation force, vibration forms of vibrating motors can generally be used. At the same time, such vibrating screens are also developing in the direction of large-scale and high-efficiency. Higher requirements are placed on operational efficiency and smoothness. Based on this situation, in the research of vibrating screens, the existing research results of vibrating screens should be based on the finite element analysis of vibrating motors and vibrating screens, and the research results should be actively used to ensure the operating efficiency and stability of the vibrating screens. In terms of performance, it meets the actual use requirements, and improves the overall application effect of the vibrating screen, enable the shaker to play a more active role.

One. Finite element analysis methods and steps

1. Establishing the finite element model of the vibrating screen In order to ensure the in-depth analysis of the finite element of the vibrating screen induced by the vibration motor, we need to establish a finite element model of the vibrating screen according to the structure of the vibrating screen. The structure of such a vibrating screen is mainly composed of a screen box, a vibration motor, and a vibration damping device. Its characteristics are: The screen box is supported on 4 rubber springs, and two vibration motors are installed on the two side walls of the screen body. When it works, it generates an exciting force in a certain direction to drive the screen body to reciprocate linear motion. Rubber springs are used to support and dampen vibrations, which can effectively prevent resonance and reduce the impact on the foundation. The structure diagram is as follows:

This study uses ANS YS as the analysis software. For more complex mechanical systems, it is difficult to establish a model that is completely equivalent to the actual system. Therefore, in the process of analysis, the model established is generally simplified to a certain degree according to the analysis purpose.

According to the characteristics of the vibrating screen in question, each part of the screen body is meshed with shel 93 elements, and the thickness of each part is defined by the real constants of the shell elements. The stiffness of the spring is decomposed into longitudinal stiffness and lateral stiffness. The combinl 4 units were used for simulation respectively; the vibration motor was processed with mass 21 unit to establish a stiffness area, the mass point representing the vibration motor was rigidified on the vibration motor mounting base plate, and the exciting force was applied to the mass point. It can be seen that in the establishment of the finite element model of the vibrating screen, the principles of accuracy and effectiveness should be grasped. At the same time, the mechanical structure of the vibrating screen must be fully considered to ensure that the finite element model of the vibrating screen conforms to the actual operation.

2. Modal analysis of vibrating screens When researching such vibrating screens, we must have a correct understanding of the vibration phenomenon. First, the main working state of the vibrating screen is vibration. During its operation, it is necessary to ensure that it maintains the vibration state, and to reasonably control the vibration frequency and amplitude to meet its operational needs. Secondly, we must recognize the danger of resonance, prevent the vibration screen from resonating in the working process, and endanger the mechanical parts of the vibration screen.

Vibration must be considered when designing such shakers. Because vibration will cause resonance or fatigue of the structure, and thus destroy the structure, understanding the natural frequency and mode shape of the structure itself can avoid unnecessary losses due to resonance factors in use. Modal analysis is mainly used to determine the vibration characteristics of the structure, such as the natural frequency and the corresponding mode shapes. They are important parameters for the structure to withstand dynamic loads and are the basis for other types of dynamic analysis. Modal analysis of the vibration screen Is necessary. Modal analysis type in ANSYS software was used to select the modal extraction method of Block Lanczos to perform modal analysis on the finite element model of the vibrating screen body.

In the modal analysis of the vibrating screen, the main purpose is to analyze the stiffness and bearing capacity of each part during the operation of the vibrating screen. While ensuring that the equipment rigidity meets the requirements, find out the resonance frequency and reduce the harm to the vibrating screen. In addition, the role of modal analysis is to confirm the vibration characteristics of the structure. For example, each vibration frequency of the vibrating screen will find the corresponding mode shape. During the modal analysis, the dynamic load parameters mainly reflect the dynamic load value of the structure. , Which forms the basis of dynamics analysis. Therefore, in the modal analysis of the finite element model of the vibrating screen, the natural frequency value of the vibrating screen can be obtained.

It can be seen that in the modal analysis of such vibrating screens, the research is mainly on the phenomenon of vibration. At the same time, a comprehensive understanding of the vibration of the vibrating screen is needed by the finite element method, and the overall vibration is determined based on the modal analysis values. Shape and effect, thereby ensuring that modal analysis can achieve positive results. Therefore, during the analysis of the vibrating screen, the role of modal analysis is relatively obvious. Based on the results of the modal analysis, the frequency of the vibrating screen can be obtained, thereby achieving the purpose of further improving the performance of the vibrating screen. In the modal analysis of the vibrating screen, we should pay attention to the role of finite elements, and we should take the finite element method as an important analysis method.

Harmonic response analysis of vibrating screens The main purpose of this type of vibrating screens is to study and analyze the effect of the vibrating screen on the simple harmonic excitation force. The specific analysis focuses on whether the dynamic response of the screen body meets It is required that, through this analysis, the response of the vibrating screen to stress under working conditions is described, so as to summarize the stress distribution of the vibrating screen, and highlight the places with high stress in the vibrating screen. Using ANSYS software, the overall analysis of the finite element model is performed, and the harmonic response is described in detail to ensure the correctness of the harmonic response analysis. Through the operating characteristics and load distribution of this type of vibrating screen, the high stress of the vibrating screen is mainly reflected in the bottom of the screen box, the spring support and the bottom of the vibration motor.

The maximum structural strength and stiffness of the vibrating screen need to be improved. The enlargement of the vibrating screen structure will lead to an increase in the vibration mass and the exciting force. The dynamic load of the vibrating screen will also increase, which will cause greater deformation, tear the side plates, and break the beams, which will seriously affect the life of the vibrating screen. In China, the conventional static strength calculation and analog method are used in the design of vibration frequency to ignore the influence of higher modal frequency on the dynamic characteristics of the vibrating screen. High vibration force is likely to cause fatigue damage to the vibrating screen. Engineering experience tells us that even if the static strength meets the performance requirements, the vibrating screen may be damaged. Therefore, performance, structure, and strength need to be dynamically analyzed during the design process. The new structure of this type of vibrating screen is developed to meet the maximum requirements, to improve the reliability of the screening machine, and to extend the service life through dynamic design.

It can be seen that in addition to the modal analysis, the harmonic response of the vibrating screen must be analyzed to a certain degree during the research of the vibrating screen. On the basis of satisfying the use, the performance of the vibrating screen is further optimized, and it can meet the actual needs to the greatest extent.

Through research, on the basis of full consideration of the actual use and structural characteristics of the vibrating screen excited by the vibrating motor, an in-depth finite element analysis of the vibrating screen excited by the vibrating motor was performed. The research methods and analysis steps using finite element software are given. Through the research results, the structure and operation process of the vibrating screen is increased, and the important guarantee for improving the operating efficiency and stability of the vibrating screen is provided.