Determination Criterion Of Node Detaching From Die In 3D-FE Backward Tracing Simulation Of Blade Precision Forging

A blade is one of the most important mechanical components in aviation engine, precision forging is a tendency of development of blade forging technology. Preformed billet design in precision forging process of blade directly affects the quality of blade forging and the operating life of forging die, and the finite element backward simulation technology is an effective method of preformed billet design. The criterion of node separating from die is used to control the time sequence of boundary nodes detaching from die during backward simulation, the establishment of criterion of node separating from die is one of key technique problems of backward simulation, and the criterion of node separating from die will affect the accuracy of backward simulation. Therefore, the determination criterion of node detaching from die is studied during 3D finite element backward simulation of blade precision forging, and the criterion of node separating from die is applied to finite element backward simulation of precision forging process of blade. This research has great significance for developing 3D finite element backward simulation technology and improving the accuracy of preformed billet design. A brief introduction to the project and its main results are as follows:(1) According to the geometry character of final forging die and final forging, a 3D finite element backward simulation mechanics model has been proposed for precision forging process of blade by the softwares Unigraphics and HyperMesh;the direct iteration and Newton-Raphson iteration are combined to generate the initial velocity field of backward simulation;the backward simulation is ended off when all the boundary nodes just detach from die.(2) The determination criterion of node separating from die is investigated in 3D finite element backward simulation of blade precision forging. On the basis of the inverse die contact tracking method, the track fit revising method is put forward to establish the criterion of node detaching from die, and the time sequence of boundary node releasing from die is determined.(3) Based on the solution to the key technical problems of backward simulation, a 3D finite element backward simulation system in precision forging process of bladeis developed. The blade precision forging process is simulated by the backward simulation system, and the reasonable preformed billet shape of blade body is obtained.(4) The rationality of preformed billet is testified through forward simulation by software DEFORM3D. Furthermore, it is reliable that the criterion of node detaching from die in backward simulation is established by the track fit revising method.