| In the post-treatment stage of subway tunnel construction,a series of maintenance work,such as grouting,cleaning and cutting,are needed for tunnel segments.At present,the method adopted is to build a simple working platform,in which the constructors construct the tunnel wall.The working platform moves in the tunnel relying on temporarily laid tracks.To lay these temporary tracks,it is necessary to drill holes in the segments of the tunnel,which will cause certain damage to the segments,and the implementation will cost a lot of manpower and time,and the efficiency is low.Therefore,it is necessary to develop a trackless transport equipment which can be used in metro tunnels to realize the mechanized construction in the post-processing stage of Metro tunnels.According to the needs of existing projects,a self-propelled tunnel maintenance platform vehicle is developed,which mainly includes body frame,operation platform,telescopic operation platform,lifting operation platform,lifting unit platform,support device and walking mechanism.Through the force analysis of the platform car,the most disadvantageous working condition of the platform car is obtained,that is,when the inertia for ce generated by the acceleration of the platform car is the same as the gravity force along the inclined direction on the inclined curve with the largest slope and the smallest diameter.According to the design requirements of the platform car,the minimum diameter of the wire rope required is calculated to be 16 mm.Considering the impact load,the minimum breaking tension of wire rope is taken as the maximum load that may occur on the frame.According to the design objectives and working conditions,the structure of the platform car is demonstrated.Platform locomotive frame adopts space rigid frame structure,lifting unit platform uses hydraulic cylinder and pulley group for lifting;telescopic operation platform can be built on the telescopic poles installed on the left and right sides of each cross beam of platform vehicle;shearing fork lift is used for lifting unit platform;hydraulic cylinder is installed on the left and right sides of platform vehicle for supporting;walking mechanism adopts hydraulic drive and articulated side.The type is fixed at the bottom of the lower column.A ccording to the above scheme,a three-dimensional model of the main structure of the platform car is established by using Solidworks 2016.The results show that the maximum bending stress on the frame of the pl atform car body is 59.37 MPa.with Q345 low alloy structural steel,which impr oves the allowable stress of the structure,and the strength of the platform car frame meets the requirements of the installation.Requirements.Because the platform car will be affected by the working environment in the actual use process,it is necessary to use finite element software to analyze the stress distribution and displacement of the whole structure.Based on the theory of structural mechanics and material mechanics and the method of finite element calculation,this paper uses ANSYS 15.0 to analyze the comprehensive stress and total body displacement of the frame structure under different working conditions,obtains the influence degree of different factors on the structure of the platform car under different working conditions,and checks the frame a ccording to the results obtained under the most unfavorable working conditions.Strength and stiffness,the results show that the platform car meets the require ments of strength and stiffness under various working conditions,but there are problems of stress concentration.It is necessary to optimize the structure of the platform car to make the stress distribution more reasonable. |
