×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

wrong temp results in transient thermal-Ansys classic

wrong temp results in transient thermal-Ansys classic

wrong temp results in transient thermal-Ansys classic

(OP)
Hey all
(i would post this in http:~~qid=210934#post but it's closed)
-----------------------
I am simulating a micro package, Frame soldered to glass.
cooling down time is below 4ms.
my IC is a hot solder (not liquid tho) at 300°C cooling down to 25°C. no other forces, just a uniform temperature (set prior to IC) of 25 degrees.
when i run the thermal transient solution (Large displc. 100 sub steps, time the end of load stre 0.05) i get funny results, in the first 3-4 steps my frame is -5°C which maked no sence.
I tried:
- increasing load steps
- doing 2 load steps, but IC is lost when running the loadstep 2
- small displacement
nothing worked, pleae advice.
 

RE: wrong temp results in transient thermal-Ansys classic

(OP)
Guys I could really use some help here

RE: wrong temp results in transient thermal-Ansys classic

If you are doing a transient thermal solution, why are you invoking large displacement (NLGEOM)?  This is for structural solutions.

If you are doing a steady-state solution in the first load step to set the initial conditions, did you include a change to transient solution for load step 2 (through ANTYPE or TIMINT)?

Maybe it would help to use an input listing from the Verification Manual (VM109 for example) as a template and then substitute your own geometry and loads.

RE: wrong temp results in transient thermal-Ansys classic

(OP)
Kan123:
thank you for responding,
- I tried Small displacement option but it gave me the same results, so i took the large displacement maybe it can handle the ''Phase transition''. which obviously didnt.
- YES, i did switch the TIMINT on and off to include the transient in the second load step.
I think im gonna start a new thread and change my questions, right now the problem is that i do get the results but they happen way too fast (solidification happens in micro seconds!) and i think it might be a problem of my unit system.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources