General Mechanical

How to apply Element Birth & Death to simulate additive manufacturing?

• Naeel D
Subscriber

Hi all, I'm in need of assistance writing/understanding the code as a rookie for the Element Birth & Death technique for my model that I want to simulate additive manufacturing (Laser cladding). What should my approach be and how is it done?

The following is what I have been able to muster together without a good understanding (specifically for ANSYS mechanical APDL:

1. Define Transient Analysis

2. NROPT, FULL

3. !Select all nodes

4. !Select all elements attached to the nodes

5. EKILL, ALL

6. !Plot ‘live elements’ (to check whether the Ekill command is executed, you may need to turn off the PowerGraphics)

7. !Select EVERYTHING (Selects all deactivated elements)

8. EALIVE (???)

• Chandra Sekaran
Ansys Employee
1. Define Transient Analysis

2. NROPT, FULL

3. !Select all nodes

4. !Select all elements attached to the nodes

5. EKILL, ALL

6. !Plot ‘live elements’ (to check whether the Ekill command is executed, you may need to turn off the PowerGraphics

7. !Select EVERYTHING (Selects all activated and deactivated elements)

8. constrain the deactivated elements if you want them to be born in the current configuration
9. solve load step with killed elements
10. If you now want to make the killed elements alive in next load step use EALIVE (???)
11. remove constraints on dead elements as appropriate.
12. solve
• Naeel D
Subscriber

Thank you Chandra Sekaran,

In relation to my updated message in this thread below, this is the single-element group that has undergone 'Birth/Death' and with Thermal loads applied:
What would be the fastest way to use 'birth/death' for all elements of my model and apply the thermal loads? Could it be a LOOP command?

• John Doyle
Ansys Employee

While it is true that you can simulate a basic Additive Manufacturing process using EKILL and EALIVE strategically, with select logic, I would not recommend this approach.

I would refer you, instead, to the MAPDL commands listed below.  You need an Additive Suite License to use these commands; but, if you are serious about AM simulation in MAPDL, this is the way to go.

AMBUILD

AMENV

AMMAT

AMPOWDER

AMSTEP

AMSUPPORTS

AMTYPE

I would also refer you to the AM course material on the Ansys Learning Hub Ansys Mechanical Workbench Additive.

There is a chapter in this course entitled 'Mechanical APDL for Additive' that takes a deeper dive into the use of the above MAPDL commands.

• Naeel D
Subscriber

Thank you all for the responses. Due to time constraints, learning Ansys Additive/MAPDL codes may be difficult to complete in time. Therefore I have simplified my model (to a quarter of the original model above) and progresses with the following steps/code:

My issue now is it will be unrealistic to select each individual volume of ELEMENTS and apply the thermal loads to each one (as the code above implies). That would be a painstaking process! I believe it would be best to use ‘LOOP’ the command, however, I am stuck with how to use this line of code for my situation. Any advice?
Thank you