Difference between revisions of "Ideal Gas Material"

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== Constitutive Law ==
== Constitutive Law ==


This [[Material Models|MPM material]] is  
This [[Material Models|MPM material]] models an ideal gas implemented as a large-deformation, isotropic, hyperelastic material at finite deformations. Its contitutive law for pressure is:
 
     
<path>P = P_0 {T\over T_0} \thinspace{1\over J}
 
where ''J'' is determinant of the deformation tensor (''J'' = ''V''/''V''<sub>0</sub>), ''T'' is temperature, and ''P''<sub>0</sub> and ''T''<sub>0</sub> are reference conditions. The pressure P is stored in the normal stresses or &sigma;<sub>xx</sub> =&sigma;<sub>yy</sub> = &sigma;<sub>zz</sub> = -''P''. All shear stresses are zero. This material is equivalent to a hyperelastic material with strain energy function of
 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<math>W = -P_0{T\over T_0} \ln J</math>
 
This energy function is equivalent to the energy per unit initial volume for isothermal compression or expansion of an ideal gas.


== Material Properties ==
== Material Properties ==

Revision as of 11:55, 28 December 2013

Constitutive Law

This MPM material models an ideal gas implemented as a large-deformation, isotropic, hyperelastic material at finite deformations. Its contitutive law for pressure is:

      <path>P = P_0 {T\over T_0} \thinspace{1\over J}

where J is determinant of the deformation tensor (J = V/V0), T is temperature, and P0 and T0 are reference conditions. The pressure P is stored in the normal stresses or σxxyy = σzz = -P. All shear stresses are zero. This material is equivalent to a hyperelastic material with strain energy function of

      [math]\displaystyle{ W = -P_0{T\over T_0} \ln J }[/math]

This energy function is equivalent to the energy per unit initial volume for isothermal compression or expansion of an ideal gas.

Material Properties

Property Description Units Default
E Tensile modulus MPa none

History Variables

None

Examples