Damage -7.97E-02 -3.77E-03 +7.22E-02 +1.48E-01 +2.24E-01 +3.00E-01 +8.53E-01 Figure 5: Modeling of slant fracture in the necking section of a Hill specimen by the Rousselier model CONCLUSIONS Finite element models with continuum elements incorporating damage evolution as well as cohesive zone elements are capable of simulating ductile rupture of thin aluminum panels. The respective model parameters can be determined from tests on comparably small and simple specimens, namely the Kahn specimen. Both models guarantee transferability over a large range of specimen sizes, though the global balances of mechanical energies differ significantly. Crack growth is predicted as normal fracture if the common assumptions of symmetry are applied to the FE mesh, whereas tests on thin structures show a transition from normal to slant fracture. In general, damage models as well as cohesive zone models are capable of simulating slant fracture under appropriate modeling conditions. The computational consumption is considerable, however, and inhibits simulation of large amounts of crack growth. ACKNOWLEDGEMENT The presented results have been obtained in a cooperation project between PECHINEY CRV and GKSS Research Centre. The authors thank J. Ch. Ehrström, J. Heerens und D. Hellmann for providing the test data. REFERENCES 1. Harris, C., Newman, J., Piascik, R. and Starnes, J. (1989). J. Aircraft 35, pp. 307-317. 2. Rousselier, G., Devaux, J. C., Mottet, G. and Devesa, G. (1989). Nonlinear Fracture Mechanics: Volume II - Elastic-Plastic Fracture, ASTM STP 995, pp. 332-354. 3. Brocks, W., Klingbeil, D., Künecke, G. and Sun, D.-Z. (1995). in: Second Symp. on Constraint Effects, ASTM STP 1224, pp. 232-252 4. Besson, J., Brocks, W., Chabanet, O. and Steglich, D. (2001). Europ. J. of Finite Elements, to be published. 5. Kahn, N. and Imbembo, E. (1958). The Welding Journal 27, pp. 169-184,. 6. Kaufman, J. and Knoll, A. (1964). Materials Research and Standards 4, pp. 151-155. 7. Gurson, A. L. (1977). J. Engng. Materials and Technology 99, pp 2-15. 8. Needleman, A. and Tvergaard, V.(1984). J. Mech. Phys. Solids 32, pp 461-490. 9. Rose, J., Ferrante, J. and Smith, J. (1981). Phys. Review Letters 47, pp. 675-678. 10. Xu, X. and Needleman, A. (1994). J. Mech. Phys. Solids 42, pp. 1397-1434.
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