Time-dependent Co-ordinate System 4

[Matthew_19]

Hi Everyone,

I am a novice modeller looking to seek help using ABAQUS. I currently have a FORTRAN subroutine that models the laser heat source but I am struggling to move the source to exact locations across the surface, a colleague mentioned to me about using an excel spreadsheet that had time-dependent coordinates that ABAQUS could read, maybe implemented into the subroutine and the laser would move to each location via reading the coordinates file previously written in excel or similiar. Can anybody recommend tutorials or help with how to move a heat source across a surface/body based on X, Y and Z coordinates and how to make sure ABAQUS reads the file?

I would want the laser to start at a location, travel along the z-axis then move slightly down the x-axis by a known distance then repeat the scan? Etc and so on.

Many thanks

 

[Matthew_19]

There is unfortunately a FATAL ERROR, the EACTIVE can only be used with elements which are being progressive cooled, how would I make sure that the build part and substrate is affected by heat source and both cool at different rates? i.e. as there are more layers added, the substrate won't receive as much localised heat. I'd like the base plate to cool via convection and radiation and eventually clamps.

 

[Matthew_19]

Hi FEAWAY, think I understand now. Even under the cooling part in the AM Plug-in, here you would define the progressive cooling of the built part, but to apply thermal boundary conditions to base plate also, this would be done inside the model tree? (out of am plug-in) The AM plug in only defines the exact additive manufactured part?

 

[FEA way]

For cooling of the base plate you can actually use the same definition as the one from plug-in because progressive cooling will also work for elements that are active from the beginning of the analysis.

In the documentation example "Sequential thermomechanical analysis of a laser powder bed fusion build", if you download the input file you may notice that they apply progressive cooling (*FILM and *RADIATE keywords) to the set containing all elements (both build part and base plate). You should do the same.

 

[Matthew_19]

I have tried to define them as such but I got an error which states: The EACTIVE could only be used with elements that are being progressively cooled, and that was with selected the base plate (substrate) and build, so I am unsure of how to implement the whole unit? Do i need to use the function:

'OP=NEW'as described in the .inp file attached to the laser powder fusion build documentation?

 

[FEA way]

EACTIVE is output variable for elements with progressive activation. Try editing the output request so that this variable is only requested for build part. In the plug-in you should also be careful when you select the built-part. Sometimes it switches back to whole model (both parts). You can check this in keywords as well.

 

[Matthew_19]

Hi FEAWAY,

Thank you very much for all your help. i will begin working on this way tomorrow, I just ran an analysis and nothing came out right at all. I have attached the .inp file, somehow not all the elements get activated and no heat is applied to model. Can you advise where gone wrong? I am trying to simulate the same path as before ( a few alterations with corresponding .cae file) I ran and checked the .odb but didn't succeed. Any advise why? Mesh is very small already.

 

[Matthew_19]

The file won't attach maybe as too large as it's 49000kb, is there any other way to show you?

 

[Matthew_19]

Attached is .inp in ZIP format

 

[Matthew_19]

Any solutions or ideas why the elements are not activated FEAWAY?

 

[FEA way]

This is your toolpath for this build part, right ?

First thing is that it has to be denser but I assume that it's only for testing. But more importantly, I think that you should raise this path a bit (in the direction of build part's thickness) so that it's not aligned with the bottom surface of the part. Or add next pass of the nozzle right above this one. That should be done to make sure that the tool will intersect with all elements meant for activation during given pass.

Also check the bead settings and make sure that they are correct.

 

[Matthew_19]

This is correct for the toolpath build part. Do you mean that the mesh for the deposition has to be denser? Brilliant thank you very much for that advice and I shall work on that. Would you recommend making the built part mesh more dense than already? Comprising of more elements? The bead settings have been set in meters also, I think the problem lies in placing the bead width too large, therefore the catchment isn't correctly aligning with the Goldak radius.

I shall try these and get back to you. You have been great!!

 

[FEA way]

No, I meant the toolpath - it should be denser (more passes for this layer). The mesh seems good. But raising the path a bit is the first thing that should be done.

 

[Matthew_19]

Hi FEAWAY,

How do you assign what section is to be built by deposition? Do you select the element set in Material Arrival, heating and cooling?

 

[FEA way]

In the AM plug-in you can assign material arrival, heating and cooling either to the whole part instance selected in AM Parts container or to selected element sets. To use the latter option just open Material Arrival, Heating or Cooling settings and change the Region from "Use assigned build parts" to "Use element set". Then pick the right elset from the list.

 

[Matthew_19]

I've selected the material arrival, heating and cooling to the deposit part as I think this is correct. The base plate is affected by the deposition of material but is not getting built and should be active from the beginning of the analysis.

I've just ran the analysis and it exited with error:

*** ***ERROR: USER SUBROUTINE UEPACTIVATIONVOL IS MISSING

I thought this would added during the CAE?

 

[FEA way]

I’ve noticed that sometimes the selection set in AM Parts container disappears when you continue to work in CAE. Thus you should always check that proper part is selected there before you write the input file or submit the analysis. Also make sure that *Element progressive activation keyword is present in the input file and that correct elset is assigned to it.

 

[Matthew_19]

Hi FEAWAY,

Just compared your .inp file to the one I've just written and both contain the same information, the Element Progressive activation **ACTIVATE ELEMENTS , ACTIVATION = "__AM-Model-1_Material Source -1_EPA__"
"ABQ_AM.materialInput" is present. I am very unsure why this error has occurred?

 

[Matthew_19]

I have just ran both my example and yours, the analysis exits with an error, error:

***ERROR: USER SUBROUTINE UEPACTIVATIONVOL IS MISSING

which makes no sense as both .inp are almost identical

 

[FEA way]

If this keyword actually has two stars instead of one then it’s commented out. Otherwise make sure that your input file has the following keywords too:

*Parameter Table Type, name="ABQ_AM.MaterialDeposition.Bead"
...
*Parameter Table Type, name="ABQ_AM.MaterialDeposition"
...
*Event Series Type, name= "ABQ_AM.MaterialDeposition"
...
*Event Series, type= "ABQ_AM.MaterialDeposition"
...
*Table Collection, name=...
*Parameter Table, type= "ABQ_AM.MaterialDeposition.Bead"
...
*Parameter Table, type= "ABQ_AM.MaterialDeposition"
...
*Activate Elements, activation=...
...

 

[Matthew_19]

Hi FEAWAY,

I have gone through the .inp file and managed to locate all the keywords. I will attach the .inp file, but I keep getting a runtime error if i attach the whole .inp file therefore I will send only the second section that defines the AM plug in. I can't locate the problem..