Experimental Study On Load Spectrum Of Rotary Drilling Rig’s Mast

The mast is an important structural part of the rotary drilling rig. The structural design, technical capability and lifetime are essential to the rotary drilling rig. However, the overall failure rate of the mast is high in practical use. In order to decrease the failure rate, extend its service life and make the structural strength meet the project’s actual situation, it is necessary to do the load spectrum test of mast of the rotary drilling rig and compile its load spectrum under the practical working condition.This thesis focused on the mast of SR280RⅡ rotary drilling rig. By analyzing its structural and working characteristics, researchers did the dynamic stress test under the real working situation and evaluated the mast fatigue strength, based on the dynamic simulation and the finite element analysis under three different conditions including the inverted mast, drilling and lifting. Then, researchers did some research on the torsional load, pressure load and lifting force about the identification of the mast by analyzing its force condition in drilling and lifting, and made the draw-bar of power head and goose head into force sensor, and then calibrated the identification coefficients of these three loads. According to the mast’s load-time data collected under the practical working condition, special data analysis software, MyCode, was used to remove zero drift and eliminate interference. Researchers compiled the load spectrum of mast by using the rain-flow counting method and did the function model distribution fitting with the help of software Origin to understand the distribution of the Mother Sample of load spectrum. In accordance with the compilation principle of the load spectrum, after calibrating the injure compatibility for each load spectrum, researchers obtained the load spectrum which had some pragmatic significanceAll those researches will provide a valuable reference for the fatigue strength assessment, structural optimization design and the data of influencing the lifespan at the latter stage. Meanwhile, it will provide some reliable basis for the development of a new rotary drilling rig.