Capabilities

We distribute two products, ALEGRA-EM (electro-mechanics) and ALEGRA-HEDP (high ennergy density physics). The code capabilities provided by ALEGRA-EM are a subset of those provided by ALEGRA-HEDP.

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ALEGRA-EM

Alegra-EM provides two complementary classes of electromagnetics models:

  • Magnetohydrodynamics (MHD): continuum mechanics coupled with electromagnetic induction and Lorentz forces 
    • Multiphase electrical conductivity models available for about 20 materials.  
    • Mesh has resistance and inductance in the coupled circuit model.
  • Ferroelectric (FE): continuum mechanics coupled with piezo- and ferroelectricity
    • Electromechanical material models for about 10 materials.  
    • Mesh has capacitance in the coupled circuit model.

The primary features of ALEGRA-EM are:

  • The use of an Arbitrary Lagrangian-Eulerian (ALE) reference frame provides flexibility, accuracy, and reduced numerical dissipation compared to a pure Eulerian code.
  • Tight integration with Dakota provides fully-coupled parametric studies and optimization
  •  Shared utilities with CTH: inline visualization (spymaster), solid/primitive geometry insertion (diatom), legacy material models (lambda)
  • Large deformations and strong shock propagation in multiple materials
  • support for random fields and material properties that have statistical distributions, e.g. Gaussian and Weibull
  • Finite element discretization including Eulerian extended finite element methods (XFEM) in 2D and 3D
  • A hierarchy of magnetohydrodynamics models
    • low magnetic Reynolds number
    • resistive magnetohydrodynamics
    • generalized magnetohydrodynamics
  • Energy deposition and explosive burn models
  • A wide variety of material models including equation of state (EOS), yield, plasticity, ductile and brittle failure, damage, spall, and anisotropic response
    • Approximately 1000 parameterized or tabular equation of state (EOS) models for metals, gasses, explosives, ceramics, polymers and other materials
    • Approximately 100 parameterized yield strength models for solids
  • Joule heating, thermal transport, and simple models for radiating excess energy
  • 3D and 2D Cartesian coordinate systems
  • 2D axisymmetric coordinate systems
  • 2D modeling with the magnetic flux density vector components in or out of the plane, with the corresponding current density out of or in the plane, respectively
  • 3D uses a discretization based on edge and face elements that maintains the discrete flux divergence-free property during the magnetic solve and constrained transport remap stage.
  • Lumped element coupled circuit equations

ALEGRA-HEDP

ALEGRA-HEDP is our product that simulates high energy density physics. It is a superset of ALEGRA-EM, and adds the following features to the ALEGRA-EM code base:

  • Radiation transport options including single group diffusion, multi-group diffusion, and implicit Monte Carlo transport
  • In-line and tabular opacity models for emission and radiation transport.
  • Two material temperature option for highly ionized plasmas with long ion-electron equilibration times