# General behaviors: These behaviors are unrestricted.

Behavior	Keyword	Requires
Material damping	*DAMPING	Elasticity, fabric, hyperelasticity, hyperfoam, low-density foam, or anisotropic hyperelasticity (except when used with beam or shell general sections or substructures)
Density	*DENSITY	Required in Abaqus/Explicit, except for hydrostatic fluid elements
Solution-dependent state variables	*DEPVAR
Thermal expansion	*EXPANSION

# Complete mechanical behaviors: These behaviors are mutually exclusive and exclude all behaviors listed for elasticity, plasticity, and hydrostatic fluid behaviors, including all related enhancements. However, when an element is enriched (“Modeling discontinuities as an enriched feature using the extended finite element method,” Section 10.7.1), the mechanical user material behavior can be used in conjunction with the progressive damage and failure behavior, which is in the enhancement for elasticity or plasticity behaviors category.

Behavior	Keyword	Requires
Acoustic medium	*ACOUSTIC MEDIUM	Density
Deformation plasticity(S)	*DEFORMATION PLASTICITY
Mechanical user material	*USER MATERIAL (, TYPE=MECHANICAL in Abaqus/Standard)

# Elasticity, fabric, and equation of state behaviors: These behaviors are mutually exclusive.

Behavior	Keyword	Requires
Elasticity	*ELASTIC
Equation of state(E)	*EOS
Fabric(E)	*FABRIC
Hyperelasticity	*HYPERELASTIC
Hyperfoam	*HYPERFOAM

Behavior	Keyword	Requires
Anisotropic hyperelasticity	*ANISOTROPIC HYPERELASTIC
Hypoelasticity(S)	*HYPOELASTIC
Porous elasticity (S)	*POROUS ELASTIC
Low-density foam (E)	*LOW DENSITY FOAM

Enhancements for elasticity behaviors:

Behavior	Keyword	Requires
Elastic shear behavior for an equation of state(E)	*ELASTIC, TYPE=SHEAR	Equation of state
Strain-based failure measures	*FAIL STRAIN	Elasticity
Stress-based failure measures	*FAIL STRESS	Elasticity
Hysteresis(S)	*HYSTERESIS	Hyperelasticity (excludes all plasticity behaviors and Mullins effect)
Mullins effect	*MULLINS EFFECT	Hyperelasticity (excludes hysteresis), hyperfoam or anisotropic hyperelasticity
Compressive failure theory(S)	*NO COMPRESSION	Elasticity
Tension failure theory(S)	*NO TENSION	Elasticity
Viscoelasticity	*VISCOELASTIC	Elasticity, hyperelasticity, or hyperfoam (excludes all plasticity behaviors and all associated plasticity enhancements); or anisotropic hyperelasticity
Shear viscosity for an equation of state(E)	*VISCOSITY	Equation of state

# Rate-independent plasticity behaviors: These behaviors are mutually exclusive.

Behavior	Keyword	Requires
Brittle cracking(E)	*BRITTLE CRACKING	Isotropic elasticity and brittle shear

Behavior	Keyword	Requires
Modified Drucker-Prager/Cap plasticity	*CAP PLASTICITY	Drucker-Prager/Cap plasticity hardening and isotropic elasticity or porous elasticity
Cast iron plasticity	*CAST IRON PLASTICITY	Cast iron compression hardening, cast iron tension hardening, and isotropic elasticity
Cam-clay plasticity	*CLAY PLASTICITY	Isotropic elasticity, orthotropic elasticity, or porous elasticity (in Abaqus/Standard)Isotropic elasticity or orthotropic elasticity (in Abaqus/Explicit)
Concrete(S)	*CONCRETE	Isotropic elasticity
Concrete damaged plasticity	*CONCRETE DAMAGED PLASTICITY	Concrete compression hardening, concrete tension stiffening, and isotropic elasticity
Crushable foam plasticity	*CRUSHABLE FOAM	Crushable foam hardening and isotropic elasticity
Drucker-Prager plasticity	*DRUCKER PRAGER	Drucker-Prager hardening and isotropic elasticity or porous elasticity (in Abaqus/Standard)Drucker-Prager hardening and isotropic elasticity or the combination of an equation of state and isotropic linear elastic shear behavior for an equation of state (in Abaqus/Explicit)
Plastic compaction behavior for an equation of state(E)	*EOS COMPACTION	Linear $U_s - U_p$ equation of state
Jointed material(S)	*JOINTED MATERIAL	Isotropic elasticity and a local orientation
Mohr-Coulomb plasticity	*MOHR COULOMB	Mohr-Coulomb hardening and isotropic elasticity
Metal plasticity	*PLASTIC	Elasticity or hyperelasticity (in Abaqus/Standard)Isotropic elasticity, orthotropic elasticity (requires anisotropic yield), hyperelasticity, or the combination of an equation of state and isotropic linear elastic shear behavior for an equation of state (in Abaqus/Explicit)

# Rate-dependent plasticity behaviors: These behaviors are mutually exclusive, except metal creep and time-dependent volumetric swelling.

Behavior	Keyword	Requires
$Cap creep^{(S)}$	*CAP CREEP	Elasticity, modified Drucker-Prager/Cap plasticity, and Drucker-Prager/Cap plasticity hardening
$Metal creep^{(S)}$	*CREEP	Elasticity (except when used to define rate-dependent gasket behavior; excludes all rate-independent plasticity behaviors except metal plasticity)
$Drucker-Prager creep^{(S)}$	*DRUCKER PRAGER CREEP	Elasticity, Drucker-Prager plasticity, and Drucker-Prager hardening
Metal plasticity	*PLASTIC, RATE	Elasticity or hyperelasticity (in Abaqus/Standard)Isotropic elasticity, orthotropic elasticity (requires anisotropic yield), hyperelasticity, or the combination of an equation of state and isotropic linear elastic shear behavior for an equation of state (in Abaqus/Explicit)
Nonlinear viscoelasticity	*VISCOELASTIC, NONLINEAR	Hyperelasticity
Rate-dependent viscoplasticity	*RATE DEPENDENT	Drucker-Prager plasticity, crushable foam plasticity, or metal plasticity
Time-dependent volumetric swelling $^{(S)}$	*SWELLING	Elasticity (excludes all rate-independent plasticity behaviors except metal plasticity)
Two-layer viscoplasticity $^{(S)}$	*VISCOUS	Elasticity and metal plasticity

Enhancements for plasticity behaviors:

Behavior	Keyword	Requires
Annealing temperature	*ANNEAL TEMPERATURE	Metal plasticity
Brittle failure(E)	*BRITTLE FAILURE	Brittle cracking and brittle shear

Behavior	Keyword	Requires
Cyclic hardening	*CYCLIC HARDENING	Metal plasticity with nonlinear isotropic/kinematic hardening
Inelastic heat fraction	*INELASTIC HEAT FRACTION	Metal plasticity and specific heat
Oak Ridge National Laboratory constitutive model(S)	*ORNL	Metal plasticity, cycled yield stress data, and, usually, metal creep
Porous material failure criteria(E)	*POROUS FAILURE CRITERIA	Porous metal plasticity
Porous metal plasticity	*POROUS METAL PLASTICITY	Metal plasticity
Anisotropic yield/creep	*POTENTIAL	Metal plasticity, metal creep, Cam-clay plasticity, or two-layer viscoplasticity
Shear failure(E)	*SHEAR FAILURE	Metal plasticity
Tension cutoff	*TENSION CUTOFF	Mohr-Coulomb plasticity

Enhancement for elasticity or plasticity behaviors:

Behavior	Keyword	Requires
Tensile failure(E)	*TENSILE FAILURE	Metal plasticity or equation of state
Damage initiation	*DAMAGE INITIATION	For elasticity behaviors: elasticity based on a traction-separation description for cohesive elements or elasticity model for fiber-reinforced composites For plasticity behaviors: elasticity and metal plasticity or Drucker-Prager plasticity
Damage evolution	*DAMAGE EVOLUTION	Damage initiation
Damage stabilization	*DAMAGE STABILIZATION	Damage evolution

# Thermal behaviors: These behaviors are unrestricted but exclude thermal user materials.

Behavior	Keyword	Requires
Thermal conductivity	*CONDUCTIVITY
Volumetric heat generation(S)	*HEAT GENERATION
Latent heat	*LATENT HEAT	Density
Specific heat	*SPECIFIC HEAT	Density

# Complete thermal behavior: This behavior is unrestricted but excludes the thermal behaviors in the previous table.

Behavior	Keyword	Requires
Thermal user material(S)	*USER MATERIAL, TYPE=THERMAL	Density

# Pore fluid flow behaviors: These behaviors are unrestricted.

Behavior	Keyword	Requires
Swelling gel(S)	*GEL	Permeability, porous bulk moduli, and absorption/exsorption behavior
Moisture-driven swelling(S)	*MOISTURE SWELLING	Permeability and absorption/exsorption behavior
Permeability(S)	*PERMEABILITY
Porous bulk moduli(S)	*POROUS BULK MODULI	Permeability and either elasticity or porous elasticity
Absorption/exsorption behavior(S)	*SORPTION	Permeability

# Electrical behaviors: These behaviors are unrestricted.

Behavior	Keyword	Requires
Dielectricity(S)	*DIELECTRIC
Electrical conductivity(S)	*ELECTRICAL CONDUCTIVITY
Fraction of electric energy released as heat(S)	*JOULE HEAT FRACTION
Piezoelectricity(S)	*PIEZOELECTRIC

# Mass diffusion behaviors: These behaviors exclude all other behaviors.

Behavior	Keyword	Requires
Mass diffusivity(S)	*DIFFUSIVITY	Solubility
Solubility(S)	*SOLUBILITY	Mass diffusivity

# Hydrostatic fluid behaviors:

Behavior	Keyword	Requires
Fluid bulk modulus $^{(S)}$	*FLUID BULK MODULUS	Hydraulic fluid
Hydrostatic fluid density	*FLUID DENSITY
Fluid thermal expansion coefficient $^{(S)}$	*FLUID EXPANSION	Hydraulic fluid

# 21.2 General properties • “Density,” Section 21.2.1