Vibration Analysis And Fatigue Life Prediction Of Rotary Platform Of Rotary Drilling Rig

With the continuous construction of high-speed,subway,bridge and other public equipment,piling machinery plays a crucial role.As a kind of piling machinery,rotary drilling rig is favored by construction workers because of its multi-function and high efficiency.The load of the rotary platform is complex,the vibration is severe,and the parts are numerous,which has an important influence on the life of the whole rotary drilling rig.Therefore,it is of practical significance to carry out the life prediction of the rotary platform to improve the working performance of the whole rotary drilling rig.This paper studies the static and dynamic characteristics of the rotary platform,calculates the vibration life and analyzes and predicts the fatigue life:Firstly,the working principle and structural composition of rotary drilling rig are mastered,and the static characteristics of rotary platform are analyzed under pressure drilling condition and main winch lifting condition.Set up the finite element pattern of the slewing platform through Solidworks and Workbench software.Carry out the statics assessment of the slewing platform based on the finite element theory,Check stress,strain and lowest safety coefficient,etc,The outcomes satisfy the safety request;study the dynamic characteristics of the rotary platform,carry out modal analysis and dynamic response analysis based on workbench,Obtained that the modal frequencies of the slewing platform preclude the motor vibration rate of recurrence 105Hz and the power head vibration rate of recurrence 2.31-8.57Hz,and will not occur resonance oscillation.Count the vibration of the motor crank-connecting rod and the vibration source generated by the cylinder pressure,and get the rotary platform vibration based on the dynamic response analysis The platform is most affected by vibration at 46.8hz,and the vibration risk point is determined.The frequency domain analysis method is systematically described.The time acceleration load is transformed into the power spectral density curve by using dewesoft software;Find the material performance manual and get the S-N curve of Q345 material.Take into factors that affect the fatigue life account,compute the S-N curve of the risk point;Set the solver parameters through n Code Designlife fatigue simulation software to get the damage,life cloud diagram,stress cycle,damage distribution histogram of the rotary platform The minimum life value is3.283×10~6 number of cycles.Study the fatigue damage criterion and life prediction method,master the principle of rain flow counting method,transform the time stress load of dangerous points into two-dimensional stress spectrum through MATLAB,and process the stress amplitude and mean value based on equal life conversion method to obtain one-dimensional stress spectrum;consult BS criterion and material performance manual to obtain S-N curve of weldment and non weldment;based on linear cumulative damage principle,The nominal stress means is used to calculate the minimum life of the rotary platform as6.6604×10~4 number of cycles,and contrasted to the calculated vibration fatigue life,the life of the rotary platform is6.6604×10~4 number of cycles.