Patyuchenko
Electrical
Hello,
I am performing thermal analysis of a simple chip 3D structure. The geometry of the structure includes several volumes which are located one above another. There are also two very thin volumes located inside one of the big volumes. These thin volumes represent heat sourses. In addition there is also one hollow volume (deep trenches) situated just under the heat sourses. This hollow volume hinders from heat dissipation.
Two loads were applied to the structure model:
heat generation rate was applied to the heat sourses and constant temperature was appled to the bottom area of the structure.
The task is to perform thermal simulation and to obtain temperature distribution inside the structure.
For meshing of all the entities the SOLID90 element was used.
Simulation was performed and the following problem arised:
after the nodal solution in the central cross section of the structure is requested Results Viewer does not show temperature distribution in the part of the structure close to the heat sourses but shows a gray area only. Moreover, the temperature scale shows unreasonably small maximum temperature. This is in Power Graphics mode. However, when I switch Full Mode on I get temperature distribution in the desirable region and the reasonable maximum temperature in the scale but temperature distribution in the rest part of the structure is presented by the constant temperature of 85 C which is not really desirable.
One more fact, the printed results for Power Graphics and Full modes were the same and the maximum temperature there was the same as in the temperature scale of the Results Viewer in Full Mode.
I thought the problem was in the mesh. Therefore I performed very fine mesh in the desirable region (total number of elements was 499331 and only one warning was received which was really marginal). Simulation time was about 5 hours. Finally I obtained almost the same result as with a coarser mesh and the same gray area in the middle of the struture.
I think the problem is with the temperature scale of the Results Viewer but I cannot find information how can I adjust it manually.
If anyone has ever encountered the same or similar problem I will be very grateful to you for any help.
Thank you very much in advance.
Best regards.
I am performing thermal analysis of a simple chip 3D structure. The geometry of the structure includes several volumes which are located one above another. There are also two very thin volumes located inside one of the big volumes. These thin volumes represent heat sourses. In addition there is also one hollow volume (deep trenches) situated just under the heat sourses. This hollow volume hinders from heat dissipation.
Two loads were applied to the structure model:
heat generation rate was applied to the heat sourses and constant temperature was appled to the bottom area of the structure.
The task is to perform thermal simulation and to obtain temperature distribution inside the structure.
For meshing of all the entities the SOLID90 element was used.
Simulation was performed and the following problem arised:
after the nodal solution in the central cross section of the structure is requested Results Viewer does not show temperature distribution in the part of the structure close to the heat sourses but shows a gray area only. Moreover, the temperature scale shows unreasonably small maximum temperature. This is in Power Graphics mode. However, when I switch Full Mode on I get temperature distribution in the desirable region and the reasonable maximum temperature in the scale but temperature distribution in the rest part of the structure is presented by the constant temperature of 85 C which is not really desirable.
One more fact, the printed results for Power Graphics and Full modes were the same and the maximum temperature there was the same as in the temperature scale of the Results Viewer in Full Mode.
I thought the problem was in the mesh. Therefore I performed very fine mesh in the desirable region (total number of elements was 499331 and only one warning was received which was really marginal). Simulation time was about 5 hours. Finally I obtained almost the same result as with a coarser mesh and the same gray area in the middle of the struture.
I think the problem is with the temperature scale of the Results Viewer but I cannot find information how can I adjust it manually.
If anyone has ever encountered the same or similar problem I will be very grateful to you for any help.
Thank you very much in advance.
Best regards.