Effective and Automated Simulation of Multistage Cold-Forging Operations through Integrated 2D and 3D Analytical Technique
A five-stage cold-forging sequence serves as a representative example of multistage automatic forging operations. This sequence includes four axisymmetric forging stages followed by a non-axisymmetric stage, integrating piercing and heading processes along with folding and overlapping. This article emphasizes the importance of employing a combined 2D and 3D simulation approach to enhance accuracy, precision, and computational efficiency in the solutions
For the 2D simulations addressing the first four axisymmetric stages, quadrilateral elements were used, while tetrahedral MINI-elements were implemented in the 3D simulation of the final non-axisymmetric stage. During the fourth stage, the workpiece underwent piercing, and it was subsequently headed in the last stage. Flash formation occurred during the heading process, resulting in overlapping, which was later trimmed in a step not included in this analysis. The axisymmetric stages were modeled using a 2D simulation tool, while the final stage was analyzed in 3D by selecting one-fourth of the geometry and applying two symmetry planes. Around 80,000 tetrahedral elements were utilized, with a friction coefficient set at 0.1 and an upper die speed of -1 mm/s.
The 2D geometry from the fourth stage was rotated to form hexahedral elements, as depicted in Figure 2. The state variables for these hexahedral elements were calculated, and the mesh was then automatically converted into a tetrahedral mesh, serving as the input for the final fifth stage of the process.
The results of the simulation were remarkable regarding mesh quality, due to the application of sophisticated mesh generation techniques. By integrating 2D and 3D simulation approaches alongside intelligent tetrahedral mesh generation, we achieved a highly accurate and precise depiction of the multistage automatic cold-forging process.
Figure 2: Converting two-dimensional results to three dimensions [2]
Figure 3: Two-dimensional results of first four stages [2]
Animations –2D (Top) and 3D (Bottom)
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References:
[1] M.S. Joun, 2013, Forging Simulation (In Korean), Jinsaem Media
[2] M.C. Lee, S.H. Chung, M.S. Joun, “Automatic and precise simulation of multistage automatic cold-forging processes by combined analyses of two- and three-dimensional approaches”, International Journal of Advanced Manufacturing Technology (2009), Vol. 41, Pages 1-7
[3] “AFDEX Blog: Advanced Techniques for Cold-Forming Simulation
