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ABSTRACT In this article, we formulate a computational large‐deformation‐plasticity (LDP) periporomechanics (PPM) paradigm through a multiplicative decomposition of the deformation gradient following the notion of an intermediate stress‐free configuration. PPM is a nonlocal meshless formulation of poromechanics for deformable porous media through integral equations in which a porous material is represented by mixed material points with nonlocal poromechanical interactions. Advanced constitutive models can be readily integrated within the PPM framework. In this paper, we implement a linearly elastoplastic model with Drucker–Prager yield and post‐peak strain softening (loss of cohesion). This is accomplished using the multiplicative decomposition of the nonlocal deformation gradient and the return mapping algorithm for LDP. The paper presents a series of numerical examples that illustrate the capabilities of PPM to simulate the development of shear bands, large plastic deformations, and progressive slope failure mechanisms. We also demonstrate that the PPM results are robust and stable to the material point density (grid spacing). We illustrate the complex retrogressive failure observed in sensitive St. Monique clay that was triggered by toe erosion. The PPM analysis captures the distribution of horst and graben structures that were observed in the failed clay mass.
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A peridynamics model for strain localization analysis of geomaterials
Summary Geomaterials such as sand and clay are highly heterogeneous multiphase materials. Nonlocality (or a characteristic length scale) in modeling geomaterials based on the continuum theory can be associated with several factors, for instance, the physical interactions of material points within finite distance, the homogenization or smoothing process of material heterogeneity, and the particle or problem size‐dependent mechanical behavior (eg, the thickness of shear bands) of geomaterials. In this article, we formulate a nonlocal elastoplastic constitutive model for geomaterials by adapting a local elastoplastic model for geomaterials at a constant suction through the constitutive correspondence principle of the state‐based peridynamics theory. We numerically implement this nonlocal constitutive model via the classical return‐mapping algorithm of computational plasticity. We first conduct a one‐dimensional compression test of a soil sample at a constant suction through the numerical model with three different values of the nonlocal variable (horizon)δ. We then present a strain localization analysis of a soil sample under the constant suction and plane strain conditions with different nonlocal variables. The numerical results show that the proposed nonlocal model can be used to simulate the inception and propagation of shear banding as well as to capture the thickness of shear bands in geomaterials at a constant suction.
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- Award ID(s):
- 1659932
- PAR ID:
- 10075160
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- International Journal for Numerical and Analytical Methods in Geomechanics
- Volume:
- 43
- Issue:
- 1
- ISSN:
- 0363-9061
- Format(s):
- Medium: X Size: p. 77-96
- Size(s):
- p. 77-96
- Sponsoring Org:
- National Science Foundation
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