Heat transfer analysis with abaqus

[FEA_User]

Hello All;
I'm doing a thermal analysis with Abaqus:
1- 2 parts in contact at room temperature
2- heating one of them to 280°
3- plotting a curve Temperature = function (time) of the 2nd part
My questions are:
1- what is the recommended type of mesh element for this kind of analysis (2D or 3D, tria or quad ...) ?
2- is that matter if the 2 parts share the same nodes ( without using contact) or i should define a contact between them?
3- can i use one step for this analysis? Or i should have one step for the initial BC and one step for the heating temperature
4- is there an abaqus output in history field which calculate the average temperature of that surface in function of time

Thanks,

 

[FEA way]

1) It depends on whether the geometry of your parts makes it possible to simplify them to 2D or not and on whether they can be meshed with hexahedrons or tetrahedrons need to be used due to their complexity.
2) If they share the nodes in the interface then you don’t need any constraints. Otherwise, tie constraint should be sufficient.
3) Your description doesn’t indicate that two steps would be needed. Initial conditions are defined separately, before any analysis steps.
4) You can use the temperature output from the nodes on that surface and compute the average using Operate on XY Data.

 

[FEA_User]

Hello;
Again, thanks a lot for your support!
I'm doing a thermal analysis with Abaqus as dicribed below:
1- The initial temperature of the steel is 20°C
2- A molten plastic at 280°C is injected
what is the most appropriate modeling method:
1- use a sharing nodes in the interface in this case how can i define the thermal conductivity of materials (I don't think that Abaqus detects it automatically)
2- use a non share nodes and and connect the parts with Pair contact where I can add the thermal conductivity of material ? for this case i'm confused which one to use at the interface between plastic/steel ? the thermal conductivity of Plastic or steel??

 

[FEA way]

It's usually best to just use tie constraints in such cases. They ensure an ideal thermal connection. Contact with gap conductance is used mostly when the thermal resistance of the interface has to be modeled for some reason (e.g. due to the presence of an air gap) but the value must be obtained from tests or literature.

 

[FEA_User]

Thank you for your reply;
Should i define the conductivity with the tie contact? If it's the case wich one must be used (of plastic or of steel)?
And how can i define the initial temperature, using a BC or initial condition or it's not necessary to define it?

 

[FEA way]

Tie constraint doesn't require conductance definition. It always allows for unresisted heat flow as if the mesh was continuous.

You should define initial temperature (as an initial condition) if you want it to be different than 0.