Structural Optimization And Analysis Of Mast Of Rotary Drilling Rig

Rotary drilling rig is a widely used Pilling machine which is applied to the bridge construction,civil engineering and other pile foundation projects.Different types of drilling tools are used in different geological strata to help the rig to improve work efficiency and shorten the hole forming time.Rotary drilling rig generally has the functions of self-walking,rotating and so on.It is flexible,which can be controlled by the handle to achieve different actions.Meanwhile,the rotary drilling rig has small environmental pollution.The application conditions can be met in most areas of China construction.Mast is the chief structural part of rotary drilling rig and is an essential part of rotary drilling rig in construction.Mast is an important support of kelly bar and rotary drive.It is mainly subjected to positive pressure,bending moment and torque,and it has a large impact load.The weight of the mast has a great effect on the weight of the whole machine.On the one hand,according to the basis of the force analysis,the mast must have a certain strength and stiffness.On the other hand,according to the stability and transportation requirements of the rig,the weight of the mast should not be too heavy and the shape should not be too large.In this paper,the large-scale general finite element analysis and processing software HYPERMESH and ANSYS are used to conduct 3D modeling of the middle mast assembly of medium and small-sized rotary drilling rig.The stiffness and strength of the middle-mast are analyzed and calculated under nine working conditions.The conclusionsare shown as following according to the calculation results:(1)The middle mast of rotary drilling rig will be deformed under the restraint of turntable hinge point,cylinder support and a variety of loads.At present,there is no general evaluation standard for the stiffness or deformation of construction machinery.The results of this calculation only show the deformation of the whole structure and the trend of the deformation,which is shown by the whole deformation cloud diagram for reference only.(2)The results of static strength analysis of mid-mast structure under manifold working conditions are less than the yield strength of material,which meets the requirements of service.Some high stress areas are mainly concentrated on the bottom of the rotary hinge support,the bottom of cylinder support seat,and the guide rail etc.For the stress concentration,the quality control of welding process must be paid attention to during the processing and assembly process.To sum up,through the calculation and analysis of the mid-mast structure under nine working conditions,the structure meets the requirement of stiffness and strength in the process of operation.