Introduction

Import or create the geometry	You can either import the geometry for your model from a CAD definition or create it within Patran. For a complete description of this process, see Patran Reference Manual, Part 2: Geometry Modeling.
Define the finite element mesh	The objective of this step is to subdivide the geometry into nodes and elements. Temperatures are calculated at the nodal points in the analysis. Heat conduction takes place within the elements. This step is described briefly in Finite Elements, 47. For more complete information, see Patran Reference Manual, Part 3: Finite Element Modeling.
Define material properties	In a steady-state conduction analysis, the thermal conductivity of one or more materials must be defined. In a transient analysis, the specific heat and density of the materials must also be defined. Sophisticated analyses may also require latent heat or fluid viscosity to be defined. This step is described in Material Library, 52.
Define element properties	The elements that define the heat conduction paths in the body can be characterized geometrically as 1D, 2D, 3D, or axisymmetric. All elements have associated material properties. In addition, one-dimensional elements must have their cross-sectional properties defined, and shell elements must have their thickness defined. This step is described in Finite Element Properties, 57.
Define loads and boundary conditions	Defining loads and boundary conditions is often the most difficult step in building a model for thermal analysis. In a steady-state analysis, fixed temperatures can be specified at any nodal points in the model. This applies to structural nodal points as well as ambient nodal points. In a transient analysis, temperatures specified on nodal points may be fixed or time varying. In addition to specifying temperatures, you can apply numerous other boundary conditions, including several forms of convection and radiation. Applied surface or volumetric heat flux or heat flow are described as thermal loads. Initial temperatures are specified for two primary reasons. In a transient analysis, the full mathematical description of the Fourier problem requires the statement of the initial condition, for heat transfer the beginning temperature. In a nonlinear steady-state analysis, the MD Nastran solver necessarily employs an iterative scheme in solving the system equations, and it requires a starting temperature to initialize the process. For more information, see Loads and Boundary Conditions, 66.

Import or create the geometry

You can either import the geometry for your model from a CAD definition or create it within Patran. For a complete description of this process, see Patran Reference Manual, Part 2: Geometry Modeling.

Define the finite element mesh

The objective of this step is to subdivide the geometry into nodes and elements. Temperatures are calculated at the nodal points in the analysis. Heat conduction takes place within the elements. This step is described briefly in Finite Elements, 47. For more complete information, see Patran Reference Manual, Part 3: Finite Element Modeling.

Define material properties

In a steady-state conduction analysis, the thermal conductivity of one or more materials must be defined. In a transient analysis, the specific heat and density of the materials must also be defined. Sophisticated analyses may also require latent heat or fluid viscosity to be defined. This step is described in Material Library, 52.

Define element properties

The elements that define the heat conduction paths in the body can be characterized geometrically as 1D, 2D, 3D, or axisymmetric. All elements have associated material properties. In addition, one-dimensional elements must have their cross-sectional properties defined, and shell elements must have their thickness defined. This step is described in Finite Element Properties, 57.

Define loads and boundary conditions

Defining loads and boundary conditions is often the most difficult step in building a model for thermal analysis. In a steady-state analysis, fixed temperatures can be specified at any nodal points in the model. This applies to structural nodal points as well as ambient nodal points. In a transient analysis, temperatures specified on nodal points may be fixed or time varying.

In addition to specifying temperatures, you can apply numerous other boundary conditions, including several forms of convection and radiation. Applied surface or volumetric heat flux or heat flow are described as thermal loads. Initial temperatures are specified for two primary reasons. In a transient analysis, the full mathematical description of the Fourier problem requires the statement of the initial condition, for heat transfer the beginning temperature. In a nonlinear steady-state analysis, the MD Nastran solver necessarily employs an iterative scheme in solving the system equations, and it requires a starting temperature to initialize the process. For more information, see Loads and Boundary Conditions, 66.