## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### Time depending Temperature Load only affect for 2 seconds possible ?

• Tim Fricke
Subscriber

Hello all,

I am currently working on my master thesis and am relatively new to the simulation with Ansys. Specifically, it is about the heat simulation of an injection molding process, which is cooled with heatpipes.
Before working directly on a large model I want to test the concept on a simple cube.

Here I already have the first problem. As a default I have a temperature of 220°C for 2 seconds on one surface. After that no temperature should be present. this process should be repeated cyclically and simulate the injection.

Is there a way to let the temperature affect only for 2 seconds ?
So far I have only found the possibility to simulate the temperature curve with a table on the surface. Because I do not have the exact values, this is difficult to do.

I hope someone can help me and thanks already :)

• Sampat Kumar
Ansys Employee

Hi Tim,
I think you should use the element birth and death technique to simulate this process. Assign the temperature value for alive and then use death for the subsequent steps. Enter the number of steps in the analysis setting as per your requirements and adjust the time for that. I have attached the following link regarding death and birth techniques that might be helpful for you.

Chapter 8: Element Birth and Death (ansys.com)
https://simutechgroup.com/performing-ekill-element-death-in-mechanical/#:~:text=Element%20Birth%20and%20Death%20Techniques%20%7C%20Ansys%20Workbench&text=An%20APDL%20Commands%20Object%20can,step%20number%2C%20or%20other%20criteria.

Regards,
Sampat

https://forum.ansys.com/forums/topic/how-to-access-the-ansys-online-help/

https://forum.ansys.com/forums/topic/guidelines-for-posting-on-ansys-learning-forum/#latest

• Ashish Khemka
Ansys Employee

Hi Tim,

Can you also please detail the cycle? When the temperature of 220 degrees Celcius act for 2 seconds then after how much duration does the same temperature appear?

If you can create the cycle in excel you may apply the same as tabular load as well.

Regards,

Ashish Khemka

• Tim Fricke
Subscriber

The solution for the temperature curve should look similar to the graphic. However, the falling curve must result from the simulation because it depends on the material and the settings of the process.

I think the approach with Ekill and different load steps could be interesting. So maybe in the next step (when the different temperature load steps works), convection could be generated on the same surface for the cooling process.

But for that I first have to get familiar with apdl  X)

• Ashish Khemka
Ansys Employee

Hi Tim,

What you can do is apply temperature load in 2 steps. The first step is of 2sec where a temperature of 220 is applied and looking at the above plot say the second step is of 80 sec. In the next step deactivate the temperature.

Apply the convection boundary condition for the second step (deactivated in the first step). This might give you the desired plot.

Right-click on the graph at a particular step and then you can activate/ deactivate the given step.

Regards,

Ashish Khemka

• Tim Fricke
Subscriber

thank you very much, this is also a very good solution!
Is there a simple way to run this process several times and set the number of cycles via a single parameter ?

• Ashish Khemka
Ansys Employee

Hi Tim,

You can enter the data for a few cycles manually like:

Define 6 steps:

1st step - 2 sec -220 deg.C - convection deactive

2nd Step - 80s - temperature deactivate, convection active

3rd step - 82 sec -220 deg.C - convection deactive

4th Step - 162s - temperature deactivate, convection active

5th step - 164 sec -220 deg.C - convection deactive

6th Step - 244s - temperature deactivate, convection active

Also, please specify 6 steps with end time for each step being 2,80,82,162,164,244.

Regards,

Ashish Khemka