Finite element analysis of nodal release approach to model ductile fracture in metal sheets

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Finite element analysis of nodal release approach to model ductile fracture in metal sheets

Bernd-Arno Behrens, Kanwar Bir Sidhu

Institute of Metal Forming and Metal Forming Machines,An der Universität 2, 30823 Garbsen, Germany.

DOI:

https://doi.org/10.7494/cmms.2007.2.0157

Abstract:

The FE-simulation of ductile fracture processes for discrete crack propagation using nodal release approach is well established for modelling crack in metal sheet. In this method, the crack is assumed to initiate or propagate along the element edges, hence, this way new crack boundary is generated in the FE mesh. Therefore, when a critical value of fracture criterion is reached at a node then that particular node is duplicated having same initial co-ordinates, and hence under subsequent load increment a new crack is generated in the FE-mesh, thus, this way crack is extended by one or more element length per increment. Therefore, in this paper, a FEM model is presented with an attempt to model ductile fracture using the nodal release approach, which is implemented in commercial FE software – MSC.Marc® together with predefined user-subroutines. Consequently, the ability of this approaches to predict the blanked edge profile are analysed and compared with micrograph from experiments.

Cite as:

Behrens, B., & Sidhu, K. (2007). Finite element analysis of nodal release approach to model ductile fracture in metal sheets. Computer Methods in Materials Science, 7(2), 289 – 293. https://doi.org/10.7494/cmms.2007.2.0157

Article (PDF):

Keywords:

Sheet Metal Forming, Blanking, Ductile fracture, Compact Test specimen, Nodal release, FEM, MSC.Marc®

References:

Brokken, D., Brekelmans, W. A. M., Baaijens, F. P. T., 1998, Predicting the shape of blanked products: a Finite Element approach, Int. She. Met. Conference, Twente, 1, 195-204.

Chang, T. M., 1951, Shearing of metal blanks, Inst. of Metals, 78, 393-414.

Choy, C. M., Balendra, R., 1996, Experimental analysis of parameters influencing the sheared-edge profiles, 4th Int. Conference on She. Met., Twente, 101-110.

Dood, B., Bai, Y., 1987, Ductile fracture and ductility – with applications to metalworking, Academic Press, London.

Fang, G., Zeng, P., Lou, L., 2002, Finite element simulation of the effect of clearance on the forming quality in the blanking process, Mat. Process. Techn., 122, 249-254.

Goijaerts, A.M., Stegeman, Y.W., Govaert, L. E., Brokken, D., Brekelmans, W. A. M., Baaijens, F. P. T., 1998, Can a new experimental and numerical study improve metal blanking?, Int. She. Met. Conf., Volume 1, Twente, 185-194.

Goijaerts, A.M., Stegeman, Y.W., Govaert, L. E., Brokken, D., Brekelmans, W. A. M., Baaijens, F. P. T., 1998, A validated FEM model to improve metal blanking, Simulations of Materials Processing: Theory, Methods and Appl., Rotterdam, 979-984.

Hambli, R., 2001, Finite element model for fracture prediction during sheet metal blanking process, Engg. Frac. Mech., 68, 365-378.

Oyane, M., Sato, T., Okimoto, K., Shima, S., 1980, Criteria for ductile fracture and their applications, J. Mech. Work. Techn., 4, 65-81.

Schmuetsch, H.-H., 1990, Einflussgroessen auf das Schneidergebnis beim Scherschneiden von Feinblechen, Ph.D thesis, IFUM, University of Hanover.

Samuel, M., 1998, FEM simulations and experimental analysis of parameters of influence in the blanking process, Mat. Proc. Techn., 84, 97-106, (in German).

Taupin, E., Breitling, J., Wu, W-T., Altan, T., 1996, Materials fracture and burr formation in blanking results of FEM simulations and comparison with experiments, J. Mat. Proc. Techn., 59, 68-78.

Thomason, P. F., 1990, Ductile Fracture of Metals, Pergamon press.