Fatigue Analysis For The Mast Of Rotary Drilling Rig Based On ANSYS

As a construction machinery in the pile of Pouring pile,Rotary drilling rigs has a wide range of adapatation to the formation,high efficiency and environmental protection It is widely used in the pile foundation.As an important part of the rotary drilling rig.The mast not only provides guidance for the Drilling tools and as the support and force components of the main actuator for the rotary drilling rigs.To ensure that the rotary drilling rigs can work properly and safely,It is necessary to study the mast of the rotary drilling rigs based on the force structure of the mast.In this paper,make the analysis of strength,stiffness,mode and fatigue of the mast for rotary drilling rigs by finite element analysis software ANSYS,the process and conclusitons of analysis as follows:(1)Make an force analysis of the mast-lifting condition,bucket-lifing condition,drilling condition for the rotary drilling rigs,and simulate it with software MATLAB.The conclusion of simulate is that the limit state of working condition for the mast is the thrust of mast amplitude cylinder to mast when start carry out the mast;The limit state of the hoisting condition for the mast is the maximum value of the drilling force;the limit state of the drilling condition for the mast is the maximum value of the torque of power head and the reaction of the pressurized cylinder.The above analysis provides a theoretical basis for the load of statical analysis of mast.(2)Established the finite element model with software PRO/E and finte element analysis software ANSYS,make statical analysis for the mast-lifting condition,bucket-lifing condition and drilling condition with ANSYS,found out the stress distribution area and the deformation of the mast by analyzing the stress and displacement of the three working conditions.Then analysis the vibration characteristics by analyzing mode of the mast,obtained natural frequency and formation of ten modes for mast.(3)Established the mathematical model of the load for rotary drilling by analyzing the theory of broken rock for the mechanism and the parameters of the drill for the rotary drilling rigs,in this paper simulated 9 kinds of combined rock of load by MATLAB,and simulated the load of mast under four different cutting thickness of one kind of combined rock.Then this load is applied to the transient analysis of the mast and obtained the stess-time course,used the counting method to statistics the stess-time course and obtained the stess cycle by the counting method.(4)when estimated fatigue life analysis of the mast,the first step is determined the location of the fatigue life of the mast,then established the R-S-N curve equation of the mast based on the material Mechanical properties of 16 Mn and symmetry cycle and the material strength limit.Combined with linear fatigue damage theory,determined the fatigue life of the mast under four different cutting thickness of one kind of combined rock.The results show that,the fatigue life of dangerous node of mast increases with the decrease of the cutting thickness,when decease same amplitude of cutting thickness,the increased amplitude of fatigue life for the mast dangerous node increases gradually.