Thermal Conduction Through A Fin
Step 1 - Create a new Patran Thermal database.
1) Click on New from the File menu or from the Defaults Toolbar as shown.
2) Type the name of the new database as thermal_plate and click OK.
3) In the Approximate Maximum Model Dimensions box, input 0.1 and change the Analysis Type to Thermal. Click OK.
Step 2 - Create the geometry of the fin using the information from the problem statement.
1) Under the Geometry tab, click on Surface and select XYZ.
2)Input the vector of <0.1 .005 0> in the Vector Coordinates List and click Apply. There are no units in Patran, and therefore it is important to stay consistent in units.
Step 3 - Create the isotropic material: thermal conductivity of conductivity, k, of 345 W(m·°C).
1) Under the Properties tab, select Isotropic.
2) Input copper as the Material Name and then select Input Properties.
3) Input 345 as the Thermal Conductivity. Click OK and Apply.
Step 4- Create a 2D surface physical property and apply the isotropic material to the model.
1) Click on Shell under the 2D Properties section.
2) Input Fin as the Property Set Name and then click on Input Properties .
3) Click on Select Material and select copper. Enter 0.001 as the Thickness. Click OK.
4) Click on Select Application Region and then click on the Select Members box. Screen pick the surface. Click Add, OK then Apply.
Step 5 - Create boundary convection conditions: apply the heat transfer coefficient, ß, of 25 W(m2·°C) to the fin and apply the ambient temperature.
1) Select the Load/BCs tab. Under the Element Uniform section, select Convection.
2) Input Top Conv as the New Set Name, set the Target Element Type to 2D, and then click on Input Data.
3) Set Surface Option to Top. Input 25 for Top Surf Convection Coef and 20 for Ambient Temperature. Click OK.
4)Click on Select Application Region and then click on the Select Geometry Entries box. In the selection toolbar, select Surface or Face. Screen select the surface. Click Add, OK then Apply.
5) Repeat steps 2-4 using Bottom Conv as the New Set Name, and select Bottom for the Surface Option in the 3rd step.
6)Repeat steps 2-4 using Edge Conv as the New Set Name, select Edge for the Surface Option in the 3rd step, and using Edge from the selection toolbar select the right edge for the Application Region.
Step 6 - Create the temperature of 100°C along the left side of the fin.
1) Click on Temperature under the Nodal section.
2) Input Temp as the New Set Name and click on Input Data.
3) Input 100 as the Boundary Temperature. Click OK.
4) Click on Select Application Region and then screen select the left edge of the surface. Click Add, OK then Apply.
Step 7 - Create a finite element surface mesh by creating 4 mesh seeds and creating a mesh with a Global Edge Length of 0.005.
1) Under the Meshing tab, click on Uniform Mesh Seeds.
2)Set the Number of Elements to 4. Click on the Curve List box and screen select the bottom curve. Click on Apply.
3) Click on Surface Meshers. Click on the Select Surface List box. Screen click the surface and input 0.005 as the Global Edge Length. Click Apply.
Step 8 - Run a steady state analysis using MSC Nastran.
1) Under the Analysis tab, select Entire Model. Ensure that the Job Name box is filled with a name and click Apply.
Step 9 - Attach results file, then create fringe plot. Record the temperature distribution.
1) Click on XDB under the Access Results submenu. .
2) Ensure the appropriate Job Name is selected and click Apply.
3) CUnder the Results tab, select Fringe/Deformation.
4) Plot Temperature. Click Apply.
Analytical Solution - Verify the results by calculating the analytical solution.
1) Using the governing equation below, we are able to create four elements on the surface.
2) Results: U1 = 100°C, U2 = 82.283°C, U3 = 70.732°C, U4 = 64.204°C, U5 = 62.053°C Nastran Results: U1 = 1.000000E+02°C, U2 = 8.448576E+01°C, U3 = 7.420589E+01°C, U4 = 6.832597E+01°C, U5 = 6.636874E+01°C (You can open the 'thermal_plate.f06' file with Notepad to view your results)
3) The small difference in these results is due to MD Nastrans non-linear analysis of the equation, making it more accurate.
