Characteristics And Static Analysis Of Bolt-welding Joint In TBM Split Cutterhead

Tunnel boring machine is a kind of driving equipment widely used in water conservancy,hydropower and mountain railway tunnel engineering.The cutter-head is at the front end of TBM and bears strong impact load.It is the core component of the whole system.TBM cutter head has a large diameter.For convenience of processing and transportation,it is often made separately and then connected by bolt welding.Considering the structural characteristics of the splitting cutter-head joint,this paper explores the modeling method of the bolt-weld joint.Establishes the static characteristic analysis model of the splitting cutter-head,and validates the modeling method and theory through experiments.The main work of this paper is as follows:The modeling method and principle of bolt joint surface are elaborated,and the application method of bolt pretension force is analyzed.Through the finite element calculation of two bolted plates,the maximum equivalent stress values of direct loading method and equivalent force method are almost the same,but the equivalent force method can not simulate the bolt stress situation because it does not establish a high-strength bolt model.The model of the joint surface of the split TBM cutter head and bolt is established.Select the appropriate weld body unit,analyze the advantages and disadvantages of each welding heat source and loading mode.The generation process of weld element is simulated based on the equivalent structure of cutter head joint by life and death element method.Firstly,the weld element is established,and then the element is activated sequentially in order to simulate the moving filling process of the weld.It is concluded that the welding speed and high strength bolts on the internal force of the structure should be fully considered when welding the bolt-welded joint of the cutter head.Based on the bolt joint surface modeling method and the weld element modeling method adopted in this paper,the split cutter head model is established.Considering the load characteristics and boundary conditions of the cutter head,the static calculation is carried out in the finite element software.Then the modeling method and theory are verified by experiments,and the load-displacement characteristics of the split TBM cutter head are further analyzed..