Learn how to set up a thermal analysis with all available boundary conditions, and how to use the resulting temperature field to set up a thermal stress analysis in the same nTop Notebook.
1. Defining Material Properties
To set up a material for thermal analysis, a thermal material property block must be added to the Properties list of a Material. These include conductivity and specific heat. For static analysis without thermal stress, Young’s Modulus and Poisson’s ratio are needed. If the static analysis includes thermal stress, a third property, the Isotropic Thermal Expansion Property, must be added, which includes the coefficient of thermal expansion (CTE). (An isotropic material is used in this example, but nTop supports orthographic materials as well.)
2. Thermal Analysis
The Thermal Analysis block consists of an FE Model input and a Boundary Condition List. The available boundary conditions for thermal analysis are listed below. For more information on each boundary condition block and its inputs, click on the Info Panel (the gray question mark on the right side of the block). All thermal boundary conditions are included in the example file for demonstration, but not all are necessarily needed to set up a proper thermal analysis.
Available Boundary Conditions
- Heat Generation
- Volumetric Heat Generation
- Surface Heat Flux
- Radiation Boundary Load
- Convection Boundary Load
- Temperature Restraint
3. Obtaining a Temperature Field from Thermal Analysis
Once the thermal analysis is complete, the resulting temperature is viewable through the HUD, The Temperature field chip can be dragged from the properties of the Thermal Analysis block.
4. Thermal Stress Analysis
With the temperature field defined, an applied thermal load can be applied to a static analysis just like any other structural boundary condition (such as forces, pressure, and displacement restraints). The applied temperature load will cause expansion and contraction of the material based on its CTE. An initial temperature load can be applied as a reference point for the initial expansion before the temperature load is applied, and should usually be set to the ambient temperature of the part before thermal loading.
Available Boundary Conditions
- *Any structural boundary condition*
- Applied Temperature Load
- Initial Temperature
And that’s it! You’ve successfully run a thermal analysis.
Are you still having issues? Contact the support team, and we’ll be happy to help!
I've followed the procedure in the article "How to select boundaries of an FE Mesh - FE Boundary by Body" to create my boundaries. However, when I put several faces in a single boundary and I add this FE Boundary condition to my Boundary Condition List I get the error "Invalid input type. Expected input of type boundary_condition but got fe_temperature_list". Am I doing something wrong?
This occurs because you are inputting a List (Boundary Selections) into another List. You need to combine the multiple faces in order to use the Boundary Selection in a Boundary Condition List.
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