Model Updating Based On Simulation For Dynamic Shear Process Of Flying Shear And Fatigue Strength Analysis Of Key Structures

Flying shear is a kind of equipment used by steel enterprises to shear metal materials for subsequent processing.The crank flying shear is widely applied because of its high machining efficiency and good shearing quality.The design of flying shear requires a comprehensive consideration of the interrelation and their dynamic characteristics among servo motors,reducers,flywheels,frames and shear mechanisms.In this paper,by comparison between experiment and simulation and the finite element model updating technique,the identification of parameters of dynamic characteristics of high temperature bar cut by flying shear is carried out,the specific contents are as follows:Firstly,the basic structure,working principle,working cycle and working characteristics of the shear mechanism of crank flying shear machine are analyzed deeply,the design requirements of its main parameters are put forward;The kinematics analysis and dynamics analysis of the shear mechanism completed;The optimization design of shearing mechanism is achieved by using multi-objective function optimization algorithm,and the optimal size of shear mechanism is obtained.Secondly,vertical impact energy of punching test rig is used to simulate the transverse impact energy of flying shear for cutting steel,the multiple impact test are conducted on high temperature bar to analyze the shear force history curve and fracture quality,and verify the general research method of the punching process;Through theoretical and simulation calculation,temperature variation of high temperature bar at room temperature and the relationship between the surface and the central temperature of bar are studied.Then,taking advantage of rigid plastic finite element method for plastic processing,according to the punching test,corresponding DEFORM3 D finite element numerical simulation was conducted,the parameter identification method about stress-strain curve under different strain rate and critical damage factor in material fracture criterion of high temperature bar in punching process is studied by model updating based on response surface methodology.Finally,the static analysis and transient response analysis of the bearing of the flying shear are conducted to get the quasi-static and dynamic support counterforce;Combining fatigue analysis theory and MSC.Fatigue software,fatigue analysis of the blade and blade adapter structure is carried out to obtain the fatigue life and put forward the improvement of the weakness of structure.the above research shows that the parameter identification me thod based on the combination of experiment,simulation and model updating is reasonable and effective,which in engineering can be applied to various mechanical structures of shearing high temperature bar to predict their shear capacity for different sizes bars,and put forward the improvement measures.At the same time,for shearing machine cutting different material or different section steel,this method of parameter identification is of practical guiding significance in the shear performance prediction and optimization.