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
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:
STRMOD¶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|
DAMMOD¶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.|
ACFL¶Sets the acoustic fluidization model used:
|BLOCK||Simple block-oscillation model.|
|NONE||No acoustic fluidization of the material.|
PORMOD¶Sets the porosity model used:
|NONE||No porosity model. Material assumed to be compact.|
THSOFT¶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.|