Abaqus Keywords Reference Manual  

*EOS
Specify an equation of state model.

This option is used to define a hydrodynamic material model in the form of an equation of state.

Products: Abaqus/Explicit  Abaqus/CFD  Abaqus/CAE  

Type: Model data

Level: Model  

Abaqus/CAE: Property module

Reference:

Required parameter:

TYPE

Set TYPE=IDEAL GAS for an ideal gas equation of state.

Set TYPE=IGNITION AND GROWTH for an ignition and growth equation of state; if this equation of state is used, the *REACTION RATE option and the *GAS SPECIFIC HEAT option are required.

Set TYPE=JWL for an explosive equation of state; if this equation of state is used, the *DETONATION POINT option is required.

Set TYPE=TABULAR for a tabulated equation of state that is linear in energy.

Set TYPE=USUP for a linear equation of state.

Optional parameters:

DETONATION ENERGY

This parameter can be used only in combination with TYPE=IGNITION AND GROWTH.

Set this parameter equal to the energy of detonation. The default value is 0.0.

Data line for an ideal gas equation of state (TYPE=IDEAL GAS): 

First (and only) line:

  1. Gas constant, R. (Units of JM–1–1.)

  2. The ambient pressure, (Units of FL–2). If this field is left blank, a default of is used.

Data lines for an ignition and growth equation of state (TYPE=IGNITION AND GROWTH): 

First line:

Material constants used in the equation of state for unreacted explosive.

  1. . (Units of FL–2.)

  2. . (Units of FL–2.)

  3. . (Dimensionless.)

  4. . (Dimensionless.)

  5. . (Dimensionless.)

Second line:

Material constants used in the equation of state for reacted products.

  1. . (Units of FL–2.)

  2. . (Units of FL–2.)

  3. . (Dimensionless.)

  4. . (Dimensionless.)

  5. . (Dimensionless.)

Data line for an explosive equation of state (TYPE=JWL): 

First (and only) line:

  1. Detonation wave speed, . (Units of LT–1.)

  2. A. (Units of FL–2.)

  3. B. (Units of FL–2.)

  4. . (Dimensionless.)

  5. . (Dimensionless.)

  6. . (Dimensionless.)

  7. Detonation energy density, . (Units of JM–1.)

  8. Pre-detonation bulk modulus, . (Units of FL–2.)

Data line for a tabulated equation of state (TYPE=TABULAR), where the volumetric strain values must be arranged in descending order: 

First line:

  1. . (Units of FL–2.)

  2. . (Dimensionless.)

  3. Volumetric strain . (Dimensionless.)

Repeat this data line as often as necessary to define the dependence of and on volumetric strain.

Data line for a linear equation of state (TYPE=USUP): 

First (and only) line:

  1. . (Units of LT–1.)

  2. s. (Dimensionless.)

  3. . (Dimensionless.)