Sheet forming modeling by inverse approach and pseudo inverse approach with damage effects

Author(s):  
Y.Q. Guo ◽  
Y.M. Li ◽  
W. Gati ◽  
H. Naceur
Author(s):  
Felipe Lima dos Reis Marques ◽  
Claudio Floridia ◽  
Thayane Alves Almeida ◽  
Ariovaldo Antonio Leonardi ◽  
Fabiano Fruett

2011 ◽  
Vol 399-401 ◽  
pp. 1832-1837 ◽  
Author(s):  
Ali Halouani ◽  
Yu Ming Li ◽  
Boussad Abbès ◽  
Ying Qiao Guo

A simplified method called “Pseudo Inverse Approach” (PIA) has been developed for the axi-symmetrical cold forging modeling in this paper. The traditional “Inverse Approach” (IA) based on the assumptions of the proportional loading and simplified tool actions may quickly give a fairly good strain distribution, but poor stress estimation. Meanwhile the PIA proposed in this paper not only keeps the advantages of the Inverse Approach but also gives good stress estimation by taking into account the loading history. To fulfill this aim, some kinematically admissible intermediate configurations represented by the free surface are used to consider the deformation paths without classical contact treatment. A new direct algorithm of plasticity integration has been used by using the notion of equivalent stress and the tensile curve, leading to a very fast and robust plastic integration procedure. An axi-symmetrical forging has been taken as an example to validate the PIA.


2007 ◽  
Vol 129 (4) ◽  
pp. 698-704 ◽  
Author(s):  
Y. M. Li ◽  
B. Abbès ◽  
Y. Q. Guo

A fast method called the “inverse approach” for sheet forming modeling is based on the assumptions of the proportional loading and simplified tool actions. To improve the stress estimation, the pseudo-inverse approach was recently developed: some realistic intermediate configurations are geometrically determined to consider the deformation paths; two new efficient algorithms of plastic integration are proposed to consider the loading history. In the direct scalar algorithm (DSA), an elastic unloading-reloading factor γ is introduced to deal with the bending-unbending effects; the equation in unknown stress vectors is transformed into a scalar equation using the notion of the equivalent stress, thus the plastic multiplier Δλ can be directly obtained without iterative resolution scheme. In the γ-return mapping algorithm, the equivalent plastic strain increment estimated by DSA is taken as the initial solution in Simo’s return mapping algorithm, leading to a stable, efficient, and accurate plastic integration scheme. The numerical experience has shown that these two algorithms give a considerable reduction of CPU time in the plastic integration.


2014 ◽  
Vol 23 (8) ◽  
pp. 1168-1188 ◽  
Author(s):  
Ali Halouani ◽  
Yuming Li ◽  
Boussad Abbès ◽  
Ying-Qiao Guo

This article presents an efficient pseudo-inverse approach for the damage prediction in cold forging process simulation. Pseudo-inverse approach combines the advantages of the fast inverse approach and accurate incremental approaches. Some intermediate configurations are created geometrically and corrected mechanically to well describe the deformation path. The formulation of an axi-symmetrical element based on pseudo-inverse approach is presented. A strain-based damage model is introduced in the flow theory of plasticity. A direct scalar integration algorithm of plasticity-damage is developed, leading to a fast and robust algorithm for large strain increments. The cold forging processes of two axi-symmetrical parts are simulated to validate pseudo-inverse approach by the incremental approach ABAQUS/Explicit. Pseudo-inverse approach gives very good results, but uses much less CPU time.


2011 ◽  
Vol 341-342 ◽  
pp. 242-246
Author(s):  
Mohammad Kankarani Farahani ◽  
Ahmad Assempour

A simplified efficient finite element method called the inverse approach (IA) has been developed to estimate initial blank and strain distribution in sheet metal forming. This algorithm is an inverse method since the position of points in final shape is known and their corresponding position in the initial blank should be determined. This approach deals with the geometric compatibility of finite elements, plastic deformation theory, and virtual work principle. This method often based on implicit static algorithms, sometimes causes convergence problems because of strong nonlinearities. This paper introduces an initial guess to speed up the convergence of Newton-Raphson solution. The application to a sheet forming example shows good agreement between forward incremental and IFEM results.


2012 ◽  
Vol 504-506 ◽  
pp. 613-618 ◽  
Author(s):  
Ali Halouani ◽  
Y.M. Li ◽  
Boussad Abbès ◽  
Y.Q. Guo ◽  
F.J. Meng ◽  
...  

A simplified method called “Pseudo Inverse Approach” (PIA) has been developed for axi-symmetrical cold forging modelling. The approach is based on the knowledge of the final part shape. Some intermediate configurations are introduced and corrected by using a free surface method to consider the deformation paths without classical contact treatment. A new direct algorithm of plasticity is developed using the notion of equivalent stress and the tensile curve, which leads to a very fast and robust plastic integration procedure. Numerical tests have shown that the Pseudo Inverse Approach is very fast compared to the incremental approach. In this paper, the PIA will be used in an optimization loop for the preliminary preform design in multi-stage forging processes. The optimization problem is to minimize the effective strain variation in the final part and the maximum forging force during the forging process. The numerical results of the optimization method using the PIA are compared to those using the classical incremental approaches to show the efficiency and limitations of the PIA.


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