In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite...In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material.展开更多
Springback is one of important factors influencing the forming quality of numerical control （NC） bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process...Springback is one of important factors influencing the forming quality of numerical control （NC） bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process was put forward. The method is based on springback angle model derived using analytic method and simulation results from three-dimensional （3D） rigid-plastic finite element method （FEM）. The method is validated through comparison with experimental results. The features of the method are as follows： （1） The method is high in efficiency because it combines advantages of rigid-plastic FEM and analytic method. （2） The method is satisfactory in accuracy, since the field variables used in the model is resulting from 3D rigid-plastic FEM solution, and the effects both of axial force and strain neutral axis shift have been included. （3） Research on multi-factor effects can be carried out using the method due to its advantage inheriting from rigid-plastic FEM. The method described here is also of general significance to other bending processes.展开更多
Forming of various customized bending parts,small batches,as well as numerous types of materials is a new challenges for Industry 4.0,the current control strategies can not meet the precision and flexibility requireme...Forming of various customized bending parts,small batches,as well as numerous types of materials is a new challenges for Industry 4.0,the current control strategies can not meet the precision and flexibility requirement,expected control strategy of bending processes need to not only resist unknown interferences of process condition and models,but also produce various new parts automatically and efficiently.In this paper,a precision and flexible bending control strategy based on analytical models and data models is proposed to build adaptive bending systems.New analytical prediction models for loading and unloading are established and suitable for various materials,a sequential identification strategy is proposed to search nominal properties using the four sub-optimization models.A data-based feedback model is established to prevent over-bending and eliminate online deviation.Above models are merged into a precision and flexible control strategy.The system firstly uses sub-optimization models to search the nominal point which is near to target point,secondly the system further uses feedback model to eliminate residual error between the nominal point and target point.Compared with four kinds sheet metals,the allowable ranges for variables are determined for a good convergence.The target bending angles were set to 20°,40°,and 60°.Forty parts were tracked for each kind material,the adaptive bending system converged after one iteration,and exhibited better performances.展开更多
基金Supported by Hebei Provincial Natural Science Foundation of in China(Grant Nos.E2015203244,E2016203266)Program for the Youth Top-notch Talents of Hebei Province
文摘In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material.
基金This work was supported by the National Natural Science Foundation of China for Distinguished Young Scholars （Grant No. 50225518）the Teaching and Research Award Program for 0utstanding Young Teachers in Higher Education Institution of M0E, PRCthe Aeronautical Science Foundation of China （Grant No. 04H53057）.
文摘Springback is one of important factors influencing the forming quality of numerical control （NC） bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process was put forward. The method is based on springback angle model derived using analytic method and simulation results from three-dimensional （3D） rigid-plastic finite element method （FEM）. The method is validated through comparison with experimental results. The features of the method are as follows： （1） The method is high in efficiency because it combines advantages of rigid-plastic FEM and analytic method. （2） The method is satisfactory in accuracy, since the field variables used in the model is resulting from 3D rigid-plastic FEM solution, and the effects both of axial force and strain neutral axis shift have been included. （3） Research on multi-factor effects can be carried out using the method due to its advantage inheriting from rigid-plastic FEM. The method described here is also of general significance to other bending processes.
基金Natural Science Foundation of Hebei Province Iron and Steel Joint Research Fund(Grant No.E2021203163)Hebei Provincial Natural Science Foundation of China(Grant No.E2021203210).
文摘Forming of various customized bending parts,small batches,as well as numerous types of materials is a new challenges for Industry 4.0,the current control strategies can not meet the precision and flexibility requirement,expected control strategy of bending processes need to not only resist unknown interferences of process condition and models,but also produce various new parts automatically and efficiently.In this paper,a precision and flexible bending control strategy based on analytical models and data models is proposed to build adaptive bending systems.New analytical prediction models for loading and unloading are established and suitable for various materials,a sequential identification strategy is proposed to search nominal properties using the four sub-optimization models.A data-based feedback model is established to prevent over-bending and eliminate online deviation.Above models are merged into a precision and flexible control strategy.The system firstly uses sub-optimization models to search the nominal point which is near to target point,secondly the system further uses feedback model to eliminate residual error between the nominal point and target point.Compared with four kinds sheet metals,the allowable ranges for variables are determined for a good convergence.The target bending angles were set to 20°,40°,and 60°.Forty parts were tracked for each kind material,the adaptive bending system converged after one iteration,and exhibited better performances.
