Showing papers by "Taylan Altan published in 1997"
TL;DR: In this article, a commercial finite element code has been modified and fracture criteria have been implemented for the study of material separation, in particular, ductile fracture is simulated by deleting the mesh elements.
42 citations
TL;DR: In this article, the performance of in-die sensors for controlling the stamping process was evaluated using a series of different sensors mounted at different locations within a progressive die, and the results of these signals were compared with load curves of mounted sensors and the acoustic emission acquired from a triaxial acceleration sensor.
39 citations
TL;DR: In this article, a combination of various line search methods with the continuation method is proposed to solve highly non-linear sheet metal forming problems, and the efficiency and robustness of these numerical procedures are compared based on a set of test examples.
Abstract: Systems of non-linear equations as they arise when analysing various physical phenomena and technological processes by the implicit Finite Element Method (FEM) are commonly solved by the Newton–Raphson method. The modelling of sheet metal forming processes is one example of highly non-linear problems where the iterative solution procedure can become very slow or diverge. This paper focuses on techniques to overcome these numerical difficulties. Several methods to generate initial guesses within the radius of convergence are proposed. Appropriate stopping criteria for the iterative procedure are discussed. A combination of various line search methods with the continuation method is proposed. The efficiency and robustness of these numerical procedures are compared based on a set of test examples. A particular form of line search was identified which allows the stable and efficient solution of highly non-linear sheet metal forming problems. Even though the present investigations were motivated by the application of the implicit FEM to the simulation of sheet metal forming processes, the findings are general enough to be applicable to a wide spectrum of non-linear FEM applications. © 1997 John Wiley & Sons, Ltd.
23 citations
TL;DR: In this paper, the authors describe the state of the art in shearing equipment and summarizes the results of simulating the shearing process by means of modified 2D Finite Element Method (FEM) code.
20 citations
TL;DR: In this paper, numerical simulation of bulk metal forming processes is increasingly applied to eliminate forming defects, predict and optimize process variables, and predict stresses in dies for preventing premature die failure.
15 citations
TL;DR: In this paper, the results of a recent study on the formability of rectangular parts from aluminum alloy 2008-T4 have been determined and BHF control methods have been developed to eliminate defects, improve part quality and increase the draw depth.
14 citations
TL;DR: In this article, the authors discussed new press techniques, die designs and milling techniques for car outer panels, and the trend goes to single acting presses with CNC-controlled multipoint cushion systems in the press table.
14 citations
24 Feb 1997
2 citations