| With the vigorous development of underwater dredging projects for ports,fairways and oceans,the dredging function and equipment for large-scale backhoe dredgers are becoming more and more abundant.At present,the BA1100 type “Jintai” backhoe dredger,which is currently in service in China,has carried out transformation of the boom structure and added a large-scale hydraulic breaker to provide an effective working equipment for channel dredging and underwater rock breaking operations.While installing a breaker to perform underwater rock breaking operations,the backhoe dredger of the ship will withstand even more dynamic loads.For customers,the service life,maintenance,and repair of the backhoe dredger are all very important.Therefore,it is very necessary to analyze the static strength,dynamic characteristics and fatigue life distribution of the boom structure of the backhoe dredger equipped in the ship.At present,most of the main design criterion of China's boom structure of large-scale backhoe dredger is based on static strength.Compared with the traditional design method,the virtual prototype simulation technology can be used to determine the weaknesses of structural strength,dynamic load concentration,and weak fatigue life at the design stage.What's more,the unreasonable structural design and lifetime distribution can be avoided in advance through modification,and it is also of great significance to improve product quality,reduce maintenance costs,and increase market competitiveness.This paper uses the backhoe dredger's arm structure of BA1100 large backhoe dredger as the research object.In one hand,The load analysis and calculation of the back dredger boom structure is performed on the typical working conditions,for example: underwater dredging operation and underwater rock breaking operation.In the other hand,a finite element model and a rigid-flexible coupling virtual prototype of the backhoe dredger's boom structure were established,and the static strength,dynamic characteristics and fatigue life distribution of the boom structure under typical conditions are calculated and analyzed.Provide effective theoretical references for maintenance,prevention of fatigue fracture accidents of backhoe dredgers during use.At the same time,it provides a certain theoretical basis for guiding the design,manufacture,and installation of the breaker for the boom structure of backhoe dredger.The main research work of the thesis is as follows:(1)The load during underwater dredging operation and underwater rock breaking operation under typical working conditions is analyzed and calculated,and the load combinations for each typical operating condition were determined.Then using Soildworks 3D modeling software to establish 3D model of backhoe dredger and import it into ANSYS to establish the finite element model.And finally,static strength check is performed on the typical working conditions of underwater dredging operations and underwater rock breaking operations.(2)The finite element analysis software Patran and dynamic simulation software Adams were combined to establish a rigid-flexible coupling virtual prototype under underwater dredging conditions and underwater rock breaking conditions for backhoe dredger's arm structure.The dynamic simulation of the working cycle under each working condition was carried out,and the dynamic characteristics of the boom structure under various working conditions were analyzed.(3)Extract the load time history file from the dynamic simulation of underwater dredging and underwater rock breaking conditions in Adams and import it into Fatigue's Fatigue load manager.Then,according to the actual situation of the backhoe dredger boom structure,the S-N curve of the boom structure is corrected.Finally,fatigue life calculation and life prediction were calculated by fatigue analysis software Fatigue,loading time history of backhoe dredger boom structure,modified S-N curve,and flexible body model of components. |
PDF Full Text Request