Prediction Of Welding Deformations Of Drilling Frame On Down-The-Hole Drill Based On Inherent Strain

Abstract:Drilling frame is a key component of TD165CH DTH, is affected by shock and vibration and subject to various loads. The drilling frame is key moving part, power head mount and the carriage are mounted on the guide rail of the drill frame and slide along the guide rail. Therefore, the welding quality and precision of drilling frame directly affect the work performance and life of DTH.But slenderness ratio of drilling frame is great, the number of weld is numerous, it is difficult to ensure quality and accuracy of welding.Predict welding deformation of a drilling frame, has practical significance to reduce welding deformation and welding processes of drilling frame.This article use ANSYS software to do finite element analysis which based on the inherent strain theory.Firstly, analyzed drilling frame structure and weld type, establish a simplified model of the basic weld and do thermal elastic-plastic finite element calculations.Inherent strain expressions obtained which are decided by the maximum temperature and constraints is derived by the one-dimensional bar-spring model, and analysis the temperature field for weld basic model of weld to obtain the maximum temperature distribution. Then solving basic distribution for each weld bead according to different welding sequence. Solving the inherent strain distribution obtained on the inherent strain expressions which have the maximum temperature and constraints. Obtained the equivalent load by integrating the equivalent load.Secondly, the equivalent load as the initial load is applied to the drilling frame, and the results of the drilling frame welding deformation are got after a elastic finite element calculation. Welding deformation results showed: Drilling frame channel flange had a "wavy" distortion, the closer of rectangular steel, the greater the amount of deformation; drilling frame has longitudinal asymmetry, resulting torsional deformation and torsional deformation has greater impact on isotropic deformation; drilling frame fixed at both ends, gravitational deformation greater impact on drilling frame.Finally, the simulation width and measured values in the same channel flange and corresponding to a different channel flange width simulation and measured values plotted between flanges comparative analysis, the results showed that:the predict results of the drilling frame welding deformation is relatively accurate based on the inherent strain theory.This paper further proposes using the fixture tooling control the amount of welding deformation, finite element analysis showed that using the fixture tooling, the deformation of each direction of drilling frame are greatly reduced, and effectively reduces the influence of gravity on the drill frame deformation.