Is this properties are enough for Extrusion simulation in ABAQUS or I need to add more?

[Jay Prajapati]

Hello,
I'm doing plastic extrusion simulation in ABAQUS. so my die is of brass and Billet is of ABS material.
I have Thermal conductivity, Density, Specific heat, youngs modulus, poissions ratio, Coefficient of thermal expansion for both material.
1) Do I need more properties for both ?
2) Is plastic strain is required for Billet as it is plastic?
3) Do I need to give "thermal conductance" in interference Properties for heat transfer? or Thermal conductivity of both material is already given so no need to give thermal conductance.
4) my flow should be transient or steady flow?

 

[FEA way]

Do you use SPH or CEL method ? For fluid you will also need viscosity. For CEL you may need so called Equation of state.

You can use elastic-plastic model for ABS. Even though plasticity is meant to be used for metals, it is often utilized for polymer materials too. However be aware that it may have some negative impact on results. For more information check „Mechanical Constitutive Theories —> Plasticity for nonmetals —> Models for granular or polymer behavior” in the Abaqus Theory Guide.

Thermal conductance defined when specifying thermal contact properties is somewhat different than thermal conductivity used in material properties (compare their units). It’s hard to measure so either provide some arbitrary value or, if you want to have perfect thermal contact, simply use very high value. Or change this interaction to tie constraint.

In your case, since you want to simulate extrusion process, I think that transient is the only option.

 

[Jay Prajapati]

Thank you so much for your reply
I dont know how to check its SPH or CEL meethod? I have result but flow isnt smooth.

thats why I'm not sure I need plastic data or not as material is polymer. But I will read it.

If I dont use thermal conductance the warning comes as no thermal interaction will done. thats why I dont know this

I also tried with transient

once again thank you for your reply

 

[FEA way]

If you defined Eulerian section and assigned EC3D8R elements then it’s CEL. On the other hand if you defined solid section and assigned PC3D elements then it’s SPH.

 

[Jay Prajapati]

I have assigned Solid section and this is my element. C3D8T: An 8-node thermally coupled brick, trilinear displacement and temperature.

 

[FEA way]

These elements are used for coupled temperature-displacement analyses of solids. Can you attach some pictures (or .inp file if possible) so that it will be easier to help ?

 

[Jay Prajapati]

yes But I didnt get good flow. You can check here. When billet flows down it strikes to nozzle and distortion inside nozzle.

I already put viscosity but error comes and abaqus/standard its not possible.

I need some smooth flow and I didnt find good data for plastic like yield stress and plastic strain. I have already applied data but it comes with warning.

I dont know how to solve this problem. If you have some idea then just share with me.

 

[FEA way]

So here you assume that polymer during extrusion is a solid elastic-plastic body and when it is extruded it undergoes large plastic strains. This approach could be used for metal extrusion but in case of polymer you should rather use CFD and perform an analysis like these shown in the 3DS Academy project called „Polymer Extrusion”. You should find it easily on their website.

 

[Jay Prajapati]

I have tried with CEL and SPH but this are used for pure liquid. In my case its semi liquid. So I have to try something new. do you have some idea how can I solve this query?

 

[FEA way]

I agree that polymer during extrusion is somewhere between solid and liquid. However for the purpose of the analysis you have to decide which of these two types of matter you will simulate. In this case you are interested in the flow so I suggest treating this material as highly viscous fluid (Carreau model is often used) instead of modeling it as a viscoplastic solid. Such approach is also used in the references I’ve mentioned in the previous post. If you search for more articles you will find out that CFD is standard tool for the purpose of such simulations.

 

[Jay Prajapati]

can you tell me how can I start simulation as abaqus CFD. As I have abaqus 2018 in that only 2 option 1) abaqus standard/explicit model 2) Electromagnetic model. So I should I approach for CFD?

 

[FEA way]

Abaqus/CFD was removed in 2017 version. You can only find it in previous releases. The reason for this change in Abaqus capabilities is that now they offer new software for CFD.

 

[Jay Prajapati]

if CFD isnt available, so in 2017 or 2018 how should I approach ?

 

[FEA way]

Abaqus/CFD solver for regular flow analysis is not available but you can still use SPH and CEL methods mentioned before. It’s the only way if you can only use newer versions of Abaqus.

 

[Jay Prajapati]

ok thank you. And do you know how to count Equatio of state ? (EOS) for specially abaqus. cause when I enter viscosity data software ask for eos. without eos comes error.

 

[IRstuff]

btw, you might consider posting this kind of question in the ABAQUS forum in the future.

TTFN (ta ta for now)
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[Jay Prajapati]

thank you @IRstuff. I'm new so I have no idea. but I will do conversation there.