Theory And Modeling On Ibration And Impact Of Flexible Body Based On DTH Hammer And Sonic Drill

With the development of exploration technology and aerospace technology, the vibration and impact of flexible body are attracting more and more attention. However, as the processes of vibration and impact are very complex, many complicated problems involved have not been well solved. In this paper, by studying the piston-bit-rock system of down-the-hole hammer (DTH) and the drill pipe of sonic drill, theoretical research is carried out on the impact response of bit during the DTH drilling rock and the vibration and impact response of drill pipe during sonic drill drilling. Specific research content is as follows:Firstly, the kinematic equation of targeted rod after the impact of two typical rod structures with elastic supports is given for the first time to study the process of DTH drill bit drilling rock, and then compare the solution with the simulation results of3D piston-bit-rock model in LS-DYNA. Discuss the influences of the stiffness of rock and the impact speed of piston and the length variance of piston and rock on the impact between DTH drill bit and rock.Secondly, a mathematical model of sonic drill pipe axial vibration in saturated soft soil stratum drilling is developed. The boundary condition of the drill pipe axial vibration is determined based on the fact that when a sonic drill drills through the saturated soft soil stratum, the resonating drill pipe fluidizes the surrounding soil and remarkably reduces the friction of the soil against the drill rod. The model is subsequently solved. In-depth studies on the displacement response, dynamic stress response and the frequency control of the vibration head during drilling are carried out.Thirdly, the impact force between drill bit and rock during rock drilling is especially important for the design of rock bit. Based on the model of the sonic drill drilling through the saturated soft soil stratum, the hard soil and rocks are modeled as a spring, and the stable forced vibration response under the influence of the top driver and the transient vibration response with the resonant drill pipe as its initial condition are solved. This work is used to facilitate a study of the vibration response of the flexible drill pipe and the potential maximum impact force between the bit and rock.Based on the above studies, this paper has provided a theoretical basis for the design, analysis and optimizing of impact machine like DTH, pile driver and tamping machine; and illustrated the vibration principle of a drill pipe when a sonic drill drills and provides good evidence for the use of this procedure for the design and optimization of the sonic drill rod.