Ansys Workbench transient heat analysis question 1

[vinel]

Hi!
I'm attempting to model the thermal stresses within a composite post extrusion. It is a cylinder composed of two solids (one forming a core) with differing thermal expansion coefficients starting at an elevated temperature. The cylinder is cooled first by air (10 seconds) then by quenching in water (30 seconds).

I'm working on Ansys workbench 13.0 (I'm new to this version, having worked with 10.0 before) and started by modelling the air cooling and quenching segments separately. These models appear to be fine, and they are composed as follows;

- Steady-state Thermal (solution->setup) Transient Thermal (solution->setup) Static structural

The first stage establishes the initial temperatures, in the second I have implemented a convection on the body and in the final I have the stresses being computed. (I am ignoring radiation)

My questions are;
1. If I am attempting to model just the cooling process, does the initial steady-state thermal "contaminate" my results? (I have not linked the solution of it directly to the static structural, so I would assume this not to be the case)

2. How do I combine the two cases, going from initial temp -> 10s cooling -> 30s quenching -> stress analysis in order to gain a single stress analysis result which encompasses both the cooling then quenching.

I currently have it set up as

Steady-state Thermal (solution->setup) Transient Thermal (solution->setup to next and to Stat.Struc.) Transient Thermal (solution->setup) Static structural.

This can be seen in the attached workflow image as stage E (static structural 3). The static structural is set up to have the second transient thermal "kick in" after 10s by setting the "active row" option.

The results of this aren't as expected, so I was wondering if anyone could do a basic breakdown of how to get the two cooling stages coming in at the correct times for the static structural.

3. Would a dynamic structural be more appropriate? From the look of the problem may well be so, but I thought I would ask here while I continue to experiment.

 

[kan123]

Your link is blocked by my IT group, but I'll try to help.
1. It is the usual practice to do a steady-state solution at near-zero time to establish the initial conditions for a transient solution, so you should be OK.
2. I'm more familiar with APDL than WB, but the basics are the same. Your thermal solution will provides sets of results stored in the database at various time points of your choosing. You then do static structural solutions at as many of these points as you like (or even at intermediate points if you wish). Each static solution calls the temperature results at that time point to use as the load.
3. This problem doesn't involve modes of vibration, so you don't need to do a structural dynamic solution.