Numerical Simulation of Plastic Localization Using Fe-Mesh Realignment

Proper design of the computational algorithm is absolutely essential in order to account for the failure mechanisms that are responsible for the development of a strongly localized mode of deformation. In this paper we discuss how to simulate numerically localized behavior of the deformation due to incorporation of non-associated plastic flow and/or softening behavior in the elasto-plastic material model. The development of a localization zone of a slope stability problem is captured by the use of a FE-mesh adaptation strategy, which aims at realigning the inter-element boundaries so that the most critical kinematical failure mode is obtained. Based on the spectral properties of the characteristic material operator we define a criterion for discontinuous bifurcation. As a by-product from this criterion, we obtain critical bifurcation directions which are used to realign the element mesh in order to enhance the ability of the model to describe properly the failure kinematics. Moreover, a successful algorithm also includes consideration of stability properties of the elasto-plastic solution.

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