| Watercourse regulating project base-rock detecting system is a new type of technology equipment for underwater base-rock exploration.It is significant for protecting people's lives and properties and ensuring the production of economic construction to study and explore this detecting system,improve science and technology level and synthetic strength of precaution, increase the validity of draft for precaution.According to the test condition and existing problem of the prototype detecting system, this paper raises the overall scheme design for a new type of watercourse regulating project base-rock detecting system. Taking the new detecting system as the research object, taking optimization design techniques and finite element analyse software ANSYS as analysis tools, the optimal design of luffing mechanism of base-rock detecting system and the static and dynamic characteristics of finite element analysis for the box type telescopic jib are researched in this dissertation, and the optimal design of telescopic jib have been recommended based on the results of the FEM analysis.Firstly, the 3D geometry model was made in the platform of ANSYS using solid modeling method.Making use of the plentiful element types and powerful mesh dividing ability of ANSYS,the FEM mesh generation for the telescopic box jib has been accomplished. Using the coupling method to simulate the osculation of sliding shoe of the telescopic jib,the author made the five jibs and all sliding shoes as one whole part,and after the analysis of the structure and load of the telescopic box jib,the FEM model of the telescopic box jib has been found with the software.The paper got the result of stresses, transmutations, dangerous working conditions and dangerous stress concentrations of the telescopic box jib on different working conditions after the static FEM analysis which was done under three working conditions.In this paper, the entire telescopic box jib has been analyzed for mode by using ANSYS software too, as a result, the stable frequency and corresponding oscillating mode have been got. To testing the correctness and reliability of the FEM analysis,the structural strength and stability analysis of the telescopic box jib was testified via material mechanics method,and the result of material mechanics correspond with the FEM analysis. Based on above work,the method to improving the structure,which provided scientific theory foundation for the structure design and improving of other similar working devices,was put forward by the author.Based on the FEM analysis of the telescopic box jib,this paper made a optimization using ANSYS under the condition:regarding the strength and rigidity as restraint,regarding total weight as oject function and regarding the dimension of the jib section as design variable. The result of the optimization indicated that the section dimensions of the telescopic box jib were lessened clearly and as a result the total weight cut down about 26.4%.All this showed that the optimization object of saving material and reducing costs has been arrived. This design method can effectively reduce the box jib's weight.In the end, motion and force analysis on the three pin-connected joints of luffing mechanism of the Base Rock system are discussed in this paper. The optimization mathematic model has been built with the multi-optimization target of minimizing the pressure of luffing cylinder and the bending moment of telescopic box jib. the method of multi-objective optimum's disposal is linear weighted method. By optimizing analysis, the reasonable positions of the three pin-connected joints have been determined. Compared with the original design, the max pressure of the hydraulic luffing cylinder is reduced by 32% and the bending moment of the telescopic box jib's critical section is reduced by 7%, this method reduce power losses and improve the total performances of the Base Rock Detecting System effectively.
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