
CAE Software【Femtet】Murata Software Co., Ltd.
General
A heating chip is mounted on a substrate. The temperature gradient caused by the heating chip is calculated by thermal analysis [Watt]. This is the same as Exercise 10 of thermal analysis.
Then, the deformation due to the temperature gradient is solved by Galileo (mechanical stress analysis).
The temperature gradient caused by the heating chip is calculated by Watt
The result is forwarded to Galileo as a thermal load.
The deformation, the displacement and the mechanical stress are solved.
Unless specified in the list below, the default conditions will be applied.
Item |
Settings |
Analysis Space |
3D |
Model unit |
mm |
Select Thermal analysis and Mechanical stress analysis.
Item |
Settings |
Solvers |
Thermal analysis [Watt] |
Thermal-Analysis Type |
Steady-State Analysis |
Options |
N/A * |
* “Thermal Load” is selected by default for the thermal load-mechanical stress coupled analysis.
The Step/Thermal Load tab is set as follows.
Tab |
Setting Item |
Settings |
Step/Thermal Load * |
Reference temperature |
25[deg] |
* The reached temperatures come from the thermal analysis.
The same as Exercise 10 of thermal analysis.
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
SUB |
006_Glass_epoxy * |
1/Solid |
GND |
008_Cu * |
2/Solid |
MAINCHIP |
001_Alumina * |
3/Solid |
SUBCHIP |
001_Alumina * |
4/Solid |
HOLE |
008_Cu * |
5/Solid |
HOLE |
008_Cu * |
6/Solid |
HOLE |
008_Cu * |
7/Solid |
HOLE |
008_Cu * |
8/Solid |
HOLE |
008_Cu * |
9/Solid |
HOLE |
008_Cu * |
10/Solid |
HOLE |
008_Cu * |
11/Solid |
HOLE |
008_Cu * |
* Available from the Material DB
The heat sources of MAINCHIP and SUBCHIP are set up as follows.
Body Attribute Name |
Tab |
Settings |
MAINCHIP |
Heat Source |
0.2[W] |
SUBCHIP |
Heat Source |
0.1[W] |
The heat transfer coefficient for the natural convection is set on the bottom face of GND as follows:
The radiation from the top and the sides is omitted.
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
Bottom/Face |
Thermal |
Heat Transfer/Ambient Radiation |
Natural convection*: 1.39[W/m2/deg5/4] Room Temperature : 25[deg] |
* The coefficient for the natural convection is calculated as follows. See [Heat Transfer/Ambient Radiation] for more information.
2.51×C×(1/L)^(1/4) = 1.39 [W/m2/deg5/4]
where
C = 0.26
Size of the substrate : 0.06×0.04
L (Typical Length) = (0.06 x 0.04 x 2) / (0.06 + 0.04) = 0.048
The temperature distribution as a result of Watt is shown below.
The next figure shows the vectors of displacement as a result of Galileo following Watt.
The substrate corners which shows the low temperature are bent downward.