Manufacturing Processes
Hasan Ghafourian Nosrati; Mahdi Gerdooei
Abstract
In recent years, most industries such as the aerospace, automotive, and others have been pushed to methods for reducing costs. One of these methods is the rubber pad forming (RPF) process, which has been given more attention as a low-cost method than conventional methods. In RPF, unlike conventional ...
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In recent years, most industries such as the aerospace, automotive, and others have been pushed to methods for reducing costs. One of these methods is the rubber pad forming (RPF) process, which has been given more attention as a low-cost method than conventional methods. In RPF, unlike conventional methods which mainly use metals as tools, one of the tools will be made of elastic pads. The RPF process has attracted the attention of many researchers around the world. Researchers from Iran started their work in this field around 2001 and subsequently published several remarkable articles. The first published Iranian study of the RPF process dates back to 2003, indicating that the use of flexible tools has a history of two decades in Iran. However, in the last decade, the number of published Iranian articles in the RPF process field and the introduction of new methods based on RPF and its simulation has increased. This review article aims to outline Iran's involvement in the RPF process, and it emphasizes that Iranian researchers predominantly contribute to the RPF process through simulation, experimental endeavors, and the introduction of innovative methods utilizing flexible tools.
Forming
Mehdi Bostan Shirin; Ramin Hashemi; Ahmad Assempour
Abstract
An enhanced unfolding Inverse Finite Element Method (IFEM) has been used together with an extended strain-based forming limit diagram (EFLD) to develop a fast and reliable approach to predict the feasibility of the deep drawing process of a part and determining where the failure or defects can occur. ...
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An enhanced unfolding Inverse Finite Element Method (IFEM) has been used together with an extended strain-based forming limit diagram (EFLD) to develop a fast and reliable approach to predict the feasibility of the deep drawing process of a part and determining where the failure or defects can occur. In the developed unfolding IFEM, the meshed part is properly fold out on the flat sheet and treated as a 2D problem to reduce the computation time. The large deformation relations, nonlinear material behavior and friction conditions in the blank holder zone have also been considered to improve the accuracy and capability of the proposed IFEM. The extended strain-based forming limit diagram based on the Marciniak and Kuczynski (M-K) model has been computed and used to predict the onset of necking during sheet processing. The EFLD is built based on equivalent plastic strains and material flow direction at the end of forming. This new forming limit diagram is much less strain path dependent than the conventional forming limit diagram. Furthermore, the use and interpretation of this new diagram are easier than the stress-based forming limit diagram. Finally, two applied examples have been presented to demonstrate the capability of the proposed approach.
Forming
S. Izadpanah; S. H. Ghaderi; M. Gerdooei
Abstract
This paper investigates the earing phenomenon in deep drawing of AA3105 aluminum alloy, experimentally and numerically. Earing defect is mainly attributed to the plastic anisotropy of sheet metal. In order to control such defect, predicting the evolution of ears in sheet metal forming analyses becomes ...
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This paper investigates the earing phenomenon in deep drawing of AA3105 aluminum alloy, experimentally and numerically. Earing defect is mainly attributed to the plastic anisotropy of sheet metal. In order to control such defect, predicting the evolution of ears in sheet metal forming analyses becomes indispensable. In this regard, the present study implements the advanced yield criterion BBC2003. Based on this yield function and the associated flow rule of plasticity, the constitutive model is derived. Accordingly, a user material VUMAT subroutine is developed and adopted in the commercial finite element software ABAQUS/Explicit. Several plane stress loading problems are designed, through which, the accuracy of the developed subroutine is verified. In addition, cylindrical cups of AA3105 aluminum alloy are fabricated using a deep drawing die. The earing defect was clearly observed on the recovered parts. Using the experimentally obtained constants of BBC2003 yield criterion for this alloy in VUMAT, deep drawing of the cylindrical cups was simulated. The results demonstrate that the earing profile can successfully be predicted using BBC2003 yield function.
