Modeling Failure Initiation in Sea Ice Based on Loss of Ellipticity
The opening of leads and ridge formation in sea ice are examples of material failure analogous to failure mechanisms in other geological materials. The prediction of failure initiation should be the role of a proper constitutive equation, in addition to the usual expectation of providing an accurate correlation between stress and strain. Under certain assumptions, the loss of ellipticity is also the state at which material stability is lost and the state at which a discontinuous bifurcation appears. Since these conditions are identical, it is proposed that these states also be identified with the initiation of material failure. In addition to the location of failure, the criterion also provides the orientation of the failure surface as a surface-normal vector, and the mode of failure initiation as an eigenvector of the acoustic tensor. The eigenvector can be interpreted as the direction of the potential strong discontinuity in displacement. The underlying theory is summarized together with references that provide applications to other geological materials.
KeywordsConstitutive Equation Yield Surface Stress Path Displacement Discontinuity Material Failure
Unable to display preview. Download preview PDF.
- Bazant, Z.P., and Planas, J., 1997. Fracture and Size Effect in Concrete and Other Quasibrittle Materials. CRC Press, New York.Google Scholar
- Hadamard, J., 1903. Lecons sur la Prpagation des Ondes et les Equations de l’Hydrodynamique. Hermann, ParisGoogle Scholar
- Kreiss, H.-O., and Lorenz, J., 1989, Initial-Boundary Value Problems and the NavierStokes Equations, Academic Press, NY.Google Scholar
- Rice, J.R., 1976. The localization of plastic deformation. Theoretical and Applied Mechanics, Proc. of the 14th IUTAM Congress, pp. 207–220, North-Holland Publishing Co.Google Scholar
- Schreyer, H.L., and Zhou, S., 1995. A unified approach for predicting material failure and decohesion. Plastic and Fracture Instabilities in Materials pp. 203–214. Ed. N. Ghoniem, ASME, AMD — Vol. 200/MD — Vol. 57.Schreyer, H.L., and Neilsen, M.K., 1996a. Discontinuous bifurcation states for associated smooth plasticity and damage with isotropic elasticity. Int. J. Solids Struct. 33: 3239–3256.Google Scholar
- Steinman, P., and Willam, K., 1991. Finite elements for capturing localized failure. Arch. Appl. Mech. 61: 259–275.Google Scholar