Study On Longitudinal Vibration Mode Of Drilling Stem Based On Sonic Drilling

The technology of sonic drill uses high frequency vibration force,or combined with rotation force and pressure,to enable the drill bit to penetrate into the soft rock layer efficiently,to carry out environmental drilling,soft soil undisturbed sampling or other drilling engineering.In the whole sonic drilling system,the drill string,as the key component connecting the bit and the power head,is the displacement path from the vibration energy of the vibration head to the bit.It is very important to carry out the research on the vibration characteristics of the drill string.At the beginning of the article,it introduces the research status of audio frequency vibration drilling technology at internal or external,and on the basis of summarizing the theory of drill string longitudinal vibration,by simplifying the structure of drill string and using one-dimensional wave equation,the longitudinal vibration model equation of drill string at the initial and zero-constrained ends with fully constrained boundary conditions is derived.The analytical solution of the longitudinal vibration of the model and the analytical formula of the modal characteristic parameters(vibration mode and vibration frequency)are obtained by the modal superposition method and the separated variable method.Secondly,on the basis of introducing the modal analysis method to solve the modal parameters of the longitudinal vibration of the rod,the modal analysis method is introduced to solve the modal parameters of the longitudinal vibration of the rod,the physical expressionl of drill string is also created by using SolidWorks,and the simulation model of drill string is constructed by using ANSYS simulation system,and the modal simulation of four drill pipes with 1.5m in length and 34 mm in diameter is carried out,so,the characteristic parameters such as natural frequency,mode shape,displacement offset and stress variation of drill string model are obtained.The drilling efficiency of audio frequency vibration can be improved more effectively according to the variation characteristics of modal characteristic parameters.In order to carry out the research on the longitudinal vibration analysis of drilling tools in the ultra-deep hole and the longitudinal vibration law of the drill string under different constrained damping conditions,it is of great significance for reference.This study can not only improve the energy transfer efficiency of the audio vibration drilling,but also check the strength of the drill string and optimize its structure size by studying the stress variation characteristics of the drill string when resonance occurs.Therefore,this research is of great significance to the development of audio frequency vibration drilling technology.