PANDAS

Porous Media Adaptive Nonlinear finite element solver
based on Differential Algebraic Systems

 

Product

PANDAS is a finite element package especially designed for the solution of strongly coupled multiphasic porous media problems in solid-fluid interaction. Porous media problems occur in various fields of engineering, as e.g. in soil and rock mechanics or foam and tissue engineering. In general, porous media models include the interacting behaviour of a deforming skeleton and a pore-fluid flow. In addition, thermal as well as chemical and electrochemical phenomena may occur and can be considered within the PANDAS package. PANDAS is also available as a porous-media tool box for Abaqus.


Applications:

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  • soil and rock mechanics
  • clay and shale mechanics
  • bio- and tissue mechanics
  • general thermo-electro-chemomechanical couplings in solid-fluid interaction and related fields


Features:

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    • Models:
      • consideration of strongly coupled multiphasic problems
      • quasi-static and dynamic computations
      • 2-d (plane strain) and 3-d initial boundary-value problems
      • materially compressible and incompressible constituents
      • saturated and partially saturated solids
      • thermomechanical couplings
      • chemical and electrochemical couplings
      • consideration of electrical fields


    • Solid Materials:
      • geometrically linear and finite deformations
      • isotropic and anisotropic properties
      • combinations of elastic, viscoelastic, plastic and viscoplastic behaviour
      • associated and non-associated plasticity or viscoplasticity
      • electrically uncharged and charged solid matrices
      • non-polar (Boltzmann) and micropolar (Cosserat) materials


    • Fluid Materials:
      • compressible and incompressible pore-fluids
      • linear (Darcy) and nonlinear (Forchheimer) filter laws
      • constant and deformation-dependent permeabilities
      • isotropic and anisotropic permeabilities
      • capillary-pressure-saturation formulation (van Genuchten)
      • ionized and non-ionized fluids
      • constant and deformation-dependent diffusivities


    • Algorithms and Solvers:
      • stable implicit time integrators (Runge-Kutta schemes)
      • direct and iterative solvers (profile, BCG and GMRES solvers)
      • time adaptivity by Newton step control or embedded error estimates
      • space adaptivity by hierarchical and remeshing strategies
      • robust mixed finite element fomulations (Taylor-Hood, MINI)
      • structured implementation in C and C++
      • single processor and multi processor (MPI) versions
      • free programmable initial and boundary conditions

 

  • Handling:
    • user friendly structure
    • stable implementation on LINUX and UNIX systems
    • interactive or batch mode
    • online visualization
    • free programmable data output


Examples: click to animate in extra window (javascript required)

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  • Evolution of a plastic deformation during the digging process of an excavation
  • 2-d simulation of a hydrogel swell test reduced in concentration
  • Unbalanced fibre reinforced tension bar
  • Cook's membrane
    (transverse isotropic)