| Revolving platform（turntable for short）is an important steel structure of the rotarydrilling rig. The weight of the revolving platform occupies a large proportion in the overallweight. So adopt a better turntable structure is of great significance to improve theperformance of the rotary drilling rig.This article turned the box-turntable structure of a certain type rotary drilling rig into ani-beam structure, and on the basis of working condition analysis, established the mathematicalmodels of the rotary drilling rig under typical working conditions and worked out the forcesthat the luffing mechanism acting on the turntable. With the aid of finite element simulationsoftware ANSYS Workbench, performed the simulation analysis of statistic and modeseparately to the two turntable structures. Then made a comprehensive comparison between thetwo structures from various aspects such as the processing properties, mechanical properties,lightweight etc. Chose the i-beam structure with better performances to carry out anoptimization design with the thicknesses of the plates as the design variable and theoptimization target of reducing the weight of the turntable to minimum.The optimization results showed that: the distributions of stress, strain, displacement and safetyfactor of the optimized turntable were similar to before optimization; and both optimizedturntable and un-optimized turntable had almost the same place where the maximum stressvalue appeared in. Optimized turntable still has higher stiffness and strength margin, safetycoefficient is2.54, fully meet the job requirements. After optimized, the weight of the turntablewas reduced by19%, which made full use of the raw materials. Modal analysis of theoptimized turntable was performed and the results of the analysis verified that the naturalfrequency of the i-beam turntable was increased because of its weight reduced, which made thenatural frequency far away from the engine frequency. And the possibility of resonance occurswas further reduced. |
