2.3.1 Thermal properties

Products: ABAQUS/Standard ABAQUS/Explicit

I. Field-variable-dependent conductivity

Elements tested

C3D8HT C3D8RHT C3D8RT C3D8T C3D10MHT C3D10MT C3D20HT C3D20RHT C3D20RT C3D20T CAX4HT CAX4RHT CAX4RT CAX4T CAX6MHT CAX6MT CGAX4HT CGAX4RHT CGAX4RT CGAX4T CGAX6MHT CGAX6MT CPE4HT CPE4RHT CPE4RT CPE4T CPE6MHT CPE6MT CPE8HT CPE8RHT CPE8RT CPE8T CPEG3T CPEG4HT CPEG4RHT CPEG4RT CPEG4T CPEG6MHT CPEG6MT CPEG8HT CPEG8RHT CPEG8T CPS4RT CPS4T CPS6MT DC3D8 DC3D10 DC3D20 DC2D3 DC2D4 DC2D6 DC2D8 DC1D2

Problem description

A one-dimensional steady-state heat transfer analysis with field-variable-dependent conductivity is performed. A heat rod with constant conductivity is placed on each side of a heat rod whose conductivity is a function of predefined field variables. These field variables are varied linearly over the course of the four increments of the analysis.

Model:

Element 1: length = 1.0, area = 3.0, conductivity = 150.0

Element 2: length = 2.0, area = 3.0, conductivity = field-variable-dependent (see below)

Element 3: length = 3.0, area = 3.0, conductivity = 150.0

In ABAQUS/Standard steady-state simulations are performed using both coupled temperature-displacement elements and pure heat transfer elements to model the rods. In ABAQUS/Explicit CPE4RT elements are used to model the heat rods (unit width is assumed for each heat rod), and a transient analysis is performed. The total simulation time is 1.40 × 10⁶. This provides enough time for the transient solution to reach steady-state conditions in this problem.

Boundary conditions:

=1000.0, =0.0

Results and discussion

The temperatures on each end of the rod (nodes 2 and 3) are reported below. These temperatures match the exact results.

Input files

ABAQUS/Standard input file

fvdepcond_std_c3d8ht.inp

Field-variable-dependent conductivity; C3D8HT elements.

fvdepcond_std_c3d8rht.inp

Field-variable-dependent conductivity; C3D8RHT elements.

fvdepcond_std_c3d8rt.inp

Field-variable-dependent conductivity; C3D8RT elements.

fvdepcond_std_c3d8t.inp

Field-variable-dependent conductivity; C3D8T elements.

fvdepcond_std_c3d10mht.inp

Field-variable-dependent conductivity; C3D10MHT elements.

fvdepcond_std_c3d10mt.inp

Field-variable-dependent conductivity; C3D10MT elements.

fvdepcond_std_c3d20ht.inp

Field-variable-dependent conductivity; C3D20HT elements.

fvdepcond_std_c3d20rht.inp

Field-variable-dependent conductivity; C3D20RHT elements.

fvdepcond_std_c3d20rt.inp

Field-variable-dependent conductivity; C3D20RT elements.

fvdepcond_std_c3d20rt_post.inp

Field-variable-dependent conductivity; *POST OUTPUT analysis.

fvdepcond_std_c3d20t.inp

Field-variable-dependent conductivity; C3D20T elements.

fvdepcond_std_cax4ht.inp

Field-variable-dependent conductivity; CAX4HT elements.

fvdepcond_std_cax4rht.inp

Field-variable-dependent conductivity; CAX4RHT elements.

fvdepcond_std_cax4rt.inp

Field-variable-dependent conductivity; CAX4RT elements.

fvdepcond_std_cax4t.inp

Field-variable-dependent conductivity; CAX4T elements.

fvdepcond_std_cax6mht.inp

Field-variable-dependent conductivity; CAX6MHT elements.

fvdepcond_std_cax6mt.inp

Field-variable-dependent conductivity; CAX6MT elements.

fvdepcond_std_cgax4ht.inp

Field-variable-dependent conductivity; CGAX4HT elements.

fvdepcond_std_cgax4rht.inp

Field-variable-dependent conductivity; CGAX4RHT elements.

fvdepcond_std_cgax4rt.inp

Field-variable-dependent conductivity; CGAX4RT elements.

fvdepcond_std_cgax4t.inp

Field-variable-dependent conductivity; CGAX4T elements.

fvdepcond_std_cgax6mht.inp

Field-variable-dependent conductivity; CGAX6MHT elements.

fvdepcond_std_cgax6mt.inp

Field-variable-dependent conductivity; CGAX6MT elements.

fvdepcond_std_cpe4ht.inp

Field-variable-dependent conductivity; CPE4HT elements.

fvdepcond_std_cpe4rht.inp

Field-variable-dependent conductivity; CPE4RHT elements.

fvdepcond_std_cpe4rt.inp

Field-variable-dependent conductivity; CPE4RT elements.

fvdepcond_std_cpe4t.inp

Field-variable-dependent conductivity; CPE4T elements.

fvdepcond_std_cpe6mht.inp

Field-variable-dependent conductivity; CPE6MHT elements.

fvdepcond_std_cpe6mt.inp

Field-variable-dependent conductivity; CPE6MT elements.

fvdepcond_std_cpe8ht.inp

Field-variable-dependent conductivity; CPE8HT elements.

fvdepcond_std_cpe8rht.inp

Field-variable-dependent conductivity; CPE8RHT elements.

fvdepcond_std_cpe8rt.inp

Field-variable-dependent conductivity; CPE8RT elements.

fvdepcond_std_cpe8t.inp

Field-variable-dependent conductivity; CPE8T elements.

fvdepcond_std_cpeg3t.inp

Field-variable-dependent conductivity; CPEG3T elements.

fvdepcond_std_cpeg4ht.inp

Field-variable-dependent conductivity; CPEG4HT elements.

fvdepcond_std_cpeg4rht.inp

Field-variable-dependent conductivity; CPEG4RHT elements.

fvdepcond_std_cpeg4rt.inp

Field-variable-dependent conductivity; CPEG4RT elements.

fvdepcond_std_cpeg4t.inp

Field-variable-dependent conductivity; CPEG4T elements.

fvdepcond_std_cpeg6mht.inp

Field-variable-dependent conductivity; CPEG6MHT elements.

fvdepcond_std_cpeg6mt.inp

Field-variable-dependent conductivity; CPEG6MT elements.

fvdepcond_std_cpeg8ht.inp

Field-variable-dependent conductivity; CPEG8HT elements.

fvdepcond_std_cpeg8rht.inp

Field-variable-dependent conductivity; CPEG8RHT elements.

fvdepcond_std_cpeg8t.inp

Field-variable-dependent conductivity; CPEG8T elements.

fvdepcond_std_cps4rt.inp

Field-variable-dependent conductivity; CPS4RT elements.

fvdepcond_std_cps4t.inp

Field-variable-dependent conductivity; CPS4T elements.

fvdepcond_std_cps6mt.inp

Field-variable-dependent conductivity; CPS6MT elements.

mcdisd1nt1.inp

Field-variable-dependent conductivity; DC1D2 elements.

fvdepcond_std_dc3d8.inp

Field-variable-dependent conductivity; DC3D8 elements.

fvdepcond_std_dc3d10.inp

Field-variable-dependent conductivity; DC3D10 elements.

fvdepcond_std_dc3d20.inp

Field-variable-dependent conductivity; DC3D20 elements.

fvdepcond_std_dc2d3.inp

Field-variable-dependent conductivity; DC2D3 elements.

fvdepcond_std_dc2d4.inp

Field-variable-dependent conductivity; DC2D4 elements.

fvdepcond_std_dc2d6.inp

Field-variable-dependent conductivity; DC2D6 elements.

fvdepcond_std_dc2d8.inp

Field-variable-dependent conductivity; DC2D8 elements.

ABAQUS/Explicit input file

fvdepcond_xpl_cpe4rt.inp

Field-variable-dependent conductivity; CPE4RT elements.

II. Conductivity and specific heat

Elements tested

CPE4T CPE4RT CPEG4T DC1D3

Problem description

A simple transient heat transfer analysis of a heat link constructed with DC1D3 elements is considered in ABAQUS/Standard. In ABAQUS/Explicit CPE4RT elements are used to model the heat link. The temperature at one end of the link is fixed, while a flux is applied to the other end. The conductivity and the specific heat of the material comprising the heat link vary with prescribed values of a field variable (FV). The value of this field variable is altered with time.

In both ABAQUS/Standard and ABAQUS/Explicit a transient analysis is conducted. The total simulation time is 6.

Results and discussion

The nodal temperatures of the link confirm that the thermal properties of the material do, indeed, depend on the field variable. The actual values of the material parameters as a function of the field variable are, therefore, correct, since the temperatures were calculated from these parameters by ABAQUS.

Input files

ABAQUS/Standard input file

mcsisd1nt1.inp

Conductivity and specific heat analysis; DC1D3 elements.

fvcondspec_std_cpe4t.inp

Conductivity and specific heat analysis; CPE4T elements.

fvcondspec_std_cpeg4t.inp

Conductivity and specific heat analysis; CPEG4T elements.

ABAQUS/Explicit input file

fvcondspec_xpl_cpe4rt.inp

Conductivity and specific heat analysis; CPE4RT elements.

III. Gap conductance

Elements tested

CPEG4T C3D8RT C3D8T DC3D8 DCC3D8

Problem description

The tests in this section are set up as cases of uniform one-dimensional heat flux using generalized plane strain (ABAQUS/Standard only), and three-dimensional elements. In all ABAQUS/Standard cases a steady-state heat transfer analysis is performed. In ABAQUS/Explicit a transient analysis is performed for each case, with a simulation time chosen to ensure that steady-state conditions are reached in this problem. Particular values (gap clearance, predefined field variables, etc.) vary during the solution, which in turn influence the conductivity across the interface and, thus, the solution.