I am trying to simulate deformation of steel structure due to thermal load.
Here I do the thermal analysis first and the .rth (Result)(Solid70 is used) is saved, then while doing the structural analysis using LDREAD command, the thermal distribution is applied as structural temperature load.
I am facing a serious problem here. It is a huge .rth file size (around 120GB)!!! If the thermal and structural analysis can be done one after the other in every time step, I hope we can solve this problem. But it cannot be done because element type structural analysis cannot be done with SOILD70 and vise verse.
The analysis is to be carried out in this fashion now because the element type used for thermal analysis (SOLID70) cannot be applied with structural boundary conditions. For that the element type has to be switched to solid185.
Is there any way to define a new element type combining the capabilities of solid70 and soild185, so that it can be used for both thermal and structural analysis?
Hi:
my answer is a hand waving answer I know... I am not sure of structural-thermal combination; I would suggest you to look for hybrid elements. Or, probably you may need to write code with this capability. I understand this is a lot time consuming and energy consuming work; however, at a conceptual level, you might dare to try.. Defining element with DOF corresponding to structural {u1, u2, u3} and thermal {u....}
so basically, what I wanted to tell you have to start with governing equations defining all the DOFs. But, I know that's a lot of stuff. I doubt if I would go for that. I am also looking forward to some other replies.
You have three ways
(1) create 2 elements in every location; one for structural and other for thermal.
(2) Find one coupled element from tech docu/support group of your software.
(3) Write your own code considering displacements as well as temperature as DOFs.
Sorry all, I forgot to mention the software I am using. I am Using Ansys Mechanical APDL. While I was going through the element types yesterday, I could see an element type USER300. I has not yet tried using that. In this we can specify which all are the DOF I should incoorporate with the element . Hope this will work. If so I will report here.
Mean while if any one have a better idea than this pls help.
@ debiprsad eve though we are creating 2 elemts at same location wont they act as two structures rather than 1
If possible can you share a sample macro/routine file with me .
With regards
Kurian
I am using Solid226
http://www.kxcad.net/ansys/ansys/ansyshelp/Hlp_E_SOLID226.html
Also please check
http://www.esss.com.br/events/ansys2013/brazil/pdf/25_2_1700.pdf
Listen, if the coupling between thermal and structural analysis is one-way ( i.e. thermal then structural) then you can do with two separate FE models, the first one you obtain time-history of the nodal temperature DOF (save them into a txt or csv file as per coordinates - you can edit these by averaging if you like). The second model is for structural analysis wherein you apply the thermal loads (i.e. temperatures) at every time-step on the corresponding coordinates of the new nodes. This method is quite well established and acceptable for structural fire engineering.
Hello Kurain How did you manage to complete your model as I am in the same predicament I am conducting fire analysis of a steel structure and do not know how to combine both structural and thermal elements in one analysis.
- Badges
- Science topic