Transient thermal analysis in ANSYS

Click For Summary

Discussion Overview

The discussion centers around conducting a transient thermal analysis of a butt welded joint using ANSYS software. Participants are exploring issues related to unexpected temperature results, boundary conditions, and material properties in the simulation process.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant reports a minimum temperature of -132.52°C in the analysis despite setting an initial temperature of 22°C and applying specific boundary conditions.
  • Another participant questions the location of the minimum temperature, asking whether it occurs at a single node or over a portion of the part.
  • There is a suggestion to troubleshoot by disabling convection and radiation boundary conditions one at a time to identify potential issues.
  • A participant mentions that maximum temperatures reached 6042.8°C, raising concerns about the boundary conditions and their effects on cooling.
  • One participant inquires about the use of nonlinear material properties and suggests remeshing the geometry to see if results change.
  • Another participant asks if a cooling cycle can be applied to the assembly and mentions attempts to link transient analyses to explore cooling effects.

Areas of Agreement / Disagreement

Participants express various concerns about boundary conditions and temperature results, indicating that there is no consensus on the cause of the unexpected temperature readings. Multiple competing views and troubleshooting strategies are presented without resolution.

Contextual Notes

Participants have noted the complexity of the analysis, including the potential influence of nonlinear material properties and the need for appropriate boundary conditions. There are unresolved questions regarding the effects of cooling cycles and the impact of remeshing on results.

happytolearn
Messages
10
Reaction score
0
I want to do a transient thermal analysis in butt welded joint.The heat flow I have given 3200 watt(Q = efficiency x current x voltage = 0.8 x 160 amp x 25 volt)to the welding zone, given 20 load step(as welding is completed in 20 sec),convection co-efficient = 11.14, emissivity = .4 and applied both boundary condition convection and radiation on every surface except welding zone. But after solving the minimum temperature of the plate is coming in negative.Can anybody tell me what i am missing?
upload_2016-4-19_19-34-18.png
 
Engineering news on Phys.org
Where does this minimum temperature occur? Is it at a single node, or over a portion of the part? Also, what did you use for your starting temperature in the analysis?
 
It is coming in a region when I run the animation. I have selected the initial temperature as 22 degree centigrade
 
For troubleshooting purposes try disabling the convection and radiation boundary conditions one at a time and see if either is the culprit. I'm guessing one of those is causing an unexpected result for some reason...
 
I have tried to analyse the result by activating and deactivating one after another.But still it is coming very high temperature.One thing to mention i have applied the boundary conditions to the whole assembly(welding zone and the two plates).What can be the other possibilities for the troubleshooting?
 
upload_2016-4-21_15-9-26.png


Maximum temperature is coming 6042 .8 and minimum -132.52! Though i have selected initial temperature as 22 degree centigrade.
 
There's something weird going on with the boundary conditions, because there's really shouldn't be a cooling effect on the part based on what I'm seeing. Do you have any other boundary conditions set up other than the heat flows?
 
No i have just given heat flow,convection and radiation.should i add any other boundary condition?What is the thing i am missing. Please help.
 
Are you using nonlinear material properties? Honestly there isn't much more input we can provide without more context. Have you re-meshed the geometry with a higher density to see if the results change?
 
  • #10
yes I have used nonlinear (temperature dependent)material property. I am now trying to see the effect by remeshing according to your advice. One thing can we cool the assemble by applying cooling cycle?I have linked the transient analysis to a new transient analysis where i have omitted the load and run it for 20 second but the imported temperature has not changed.In journaIs I saw everyone cool the assemble for some time.Is there any way to run the cooling cycle in workbench?
 

Similar threads

Transient Thermal Analysis in Ansys (APDL)
  • · Replies 2 ·
Replies
2
Views
9K