Material description

iSALE includes several alternative material models. These can be selected and the relevant parameters set in the material input file. The default filename for the material input file is: material.inp.

Following the header, containing the input file identication string, the first line of the input file specifies the name of the different material models to be used in the simulation. Up to three different materials may be considered; with data entered in columns, one for each material, separated by a colon.

The example below includes two different materials, one named impactr the other named target_.
The material name should be seven characters long. It is this material name that is referred to in asteroid.inp to assign different materials to different objects and/or layers in the mesh.

#ISMAT ! iSale material input file identification string
MATNAME  Material name          : impactr : target_

For each material an equation of state (EOS) must be defined. The name of the equation of state file must be given, as well as the type of EOS. iSALE supports two EOS-types, data tables produced by ANEOS (EOSTYPE = aneos) and parameters defining the Tillotson analytical EOS (EOSTYPE = tillo).
Available EOS files (aneos and tillo) are included in the iSALE repository in the eos directory. The example below uses the dunite_.aneos ANEOS equation of state table for the impactr material and wettuff.tillo Tillotson EOS parameters for the target_ material.

EOSNAME   EOS name              : dunite_ : wettuff
EOSTYPE   EOS type              : aneos   : tillo

The next six lines of the input file are compulsory and define the strength, damage, acoustic fluidization and porosity models used in combination to complete the material model. Again, these must be specified for each material in columns, separated by a colon.

STRMOD    Strength model         : NONE   : ROCK
DAMMOD    Damage model           : NONE   : IVANOV
ACFL      Acoustic fluidisation  : NONE   : NONE
PORMOD    Porosity model         : NONE   : NONE
THSOFT    Thermal softening      : NONE   : OHNAKA
LDWEAK    Low density weakening  : NONE   : POLY

The different possible options currently are:


Sets the strength model used (see the manual for more details):
ROCK Pressure- and damage-dependent strength model for rock-like materials.
DRPR Drucker-Prager: Linear pressure-dependent strength model for granular materials.
LUNDI Lundborg intact: Non-linear pressure-dependent strength model for intact rock.
LUNDD Lundborg damaged: Non-linear pressure-dependent strength model for damaged rock.
VNMS Von Mises: Constant yield-strength model for ductile materials.
JNCK Johnson and Cook: Strain and strain-rate dependent strength model for metals.
LIQU Liquid: Newtonian fluid model
HYDRO Hydrodynamic: Inviscid fluid model


Sets the damage model used (see the relevant section below for more details):
COLLINS Combined shear and tensile failure model with brittle, semi-brittle and ductile shear failure regimes.
IVANOV Shear failure model with pressure-dependent failure strain.
SIMPLE Shear failure model with constant failure strain.
NONE No damage model; material remains intact.


Sets the acoustic fluidization model used:
BLOCK Simple block-oscillation model.
NONE No acoustic fluidization of the material.


Sets the porosity model used:
WUNNEMA Epsilon-Alpha-Compaction model
NONE No porosity model. Material assumed to be compact.


Sets the thermal softening model used:
OHNAKA Smooth hyperbolic tangent function of temperature. For use with all strength models except JNCK.
JNCK Polynomial function of temperature. For use with Johnson and Cook (JNCK) strength model.
NONE No thermal softening.