Research On Structure Optimization And Fatigue Life Of Vibrating Dewatering Screen

The vibrating screen is a widely used screening equipment,which uses the exciting force generated by the rotation of the vibrator to excite the screen to vibrate so that the mixture can be used for screening,dehydration and de-intermediation.As a key equipment in the post-treatment process of synthetic rubber,vibrating dewatering screen plays the role of conveying rubber particles and dewatering.The quality of its structure and performance has a great impact on production efficiency,dewatering effect,and equipment life.Vibrating dewatering screen is generally used in harsh environments and have long working hours.During their use,they generally have problems such as high operating noise,easy damage to key parts,and low overall service life.Therefore,in view of the above-mentioned problems,it is very necessary to systematically study the vibrating dewatering screen for rubber post-processing.This paper takes the 1857 ZTD vibrating dewatering screen of a machinery manufacturing company as the research object.On the basis of fully consulting relevant domestic and foreign documents,the working mechanism of the vibrating dewatering screen is studied,a finite element model is established,and ANSYS workbench finite element software is used.The vibrating dewatering screen was analyzed for statics,modal analysis and harmonious response analysis.According to the analysis results,its structure and process parameters were optimized,and the fatigue life of the vibrating dewatering screen was predicted using the fatigue tool module.The main research contents of this paper are as follows:(1)On the basis of fully consulting relevant domestic and foreign documents,the working mechanism of the vibrating dewatering screen was studied,the mechanical model of the vibrating screen body was established,and the vibration equation was deduced;The structure of the screen body was simplified,and a finite element model of the vibrating dewatering screen was established.(2)The static structural module in ANSYS workbench was used to analyze the statics of the vibrating dewatering screen.The dynamic and static method is used to apply the exciting force.Through static analysis and research,it was found that the total displacement of the vibrating dewatering screen is between 22.22?23.51 mm,the displacement of the upper left corner of the side plate is the largest;The stress at the connection between the spring support beam and the side plate is the largest,reaching121.31 MPa,and the safety factor is 2.3,which is slightly smaller.It is easy to cause fatigue failure too quickly under long-term alternating loads.(3)The modal analysis of the vibrating dewatering screen was carried out using the modal module of ANSYS workbench.Through modal analysis,the first 12 natural frequencies and vibration modes of the vibrating dewatering screen are obtained.The fifth natural frequency is 12.515 Hz,which is 3.785 Hz different from the 16.3 Hz operating frequency,indicating that resonance will not occur under normal working conditions.(4)Using the hydrodynamic response module of ANSYS workbench to analyze the harmonic response of the vibrating dewatering screen by using the modal superposition method.Through the research results,it was found that the vibrating dewatering screen resonated at the frequencies of 4.4475 Hz,8.9369 Hz and 12.515 H,which are exactly the same as the second,third,and fifth natural frequencies in the modal analysis.The three frequency values are all less than the working frequency of16.3Hz.Although there will be no resonance in the working state,resonance will occur at the three frequencies of 4.4475 Hz,8.9369 Hz and 12.515 Hz during the start and stop of the vibrating screen.The plates,spring support beams,beams and inner tanks produce huge amplitudes.At the same time,it can be seen that at a working frequency of 16.3 Hz,the maximum stress value at the connection between the spring support beam and the side plate is 270.07 MPa,which is close to the yield strength of the material,and there is a risk of fatigue failure.(5)Based on the above analysis results,the structure of the vibrating dewatering screen has been optimized.With the optimized structure of the vibrating dewatering screen under a static load of 60 kN,the maximum displacement is reduced from 23.15 mm to 12.36 mm,and the maximum stress value is reduced from 121.31 MPa to 51.18MPa;the resonance frequency is also changed to 4.478 Hz,10.44 Hz,17.718 Hz,the difference between the operating frequency and 16.3Hz becomes larger,the resonance points are reduced from 3 to 2 during the start and stop process;the X-axis displacement peak at the resonance point is reduced by 91.42%,and the Y-axis displacement peak Reduced by 67.83%.The optimized structure reduces the maximum stress from 270.07 MPa to 173.48 MPa under the working frequency of 16.3Hz,which reduces the risk of fatigue failure.(6)Using matlab optimization toolbox to optimize the kinematic parameters of the vibrating dewatering screen,the theoretical dewatering capacity is 9.7% higher than the initial design value.(7)Using the fatigue module of the workbench to study the life,damage,fatigue safety factor and fatigue sensitivity of the vibrating dewatering screen.The results show that the fatigue life of the vibrating dewatering screen has been extended from 0.52 years before optimization to 19.82 years,increasing the fatigue life by 37.6 times.