Evaluate tube geometrical parameters after forming operation in Abaqus/Visualization

[simulation_engineer_2022]

Hi everyone!

I have a model of tube forming operation using Abaqus/Explicit and I need to evaluate two geometrical parameters of processed tube:

1. Ovality of tube cross-section, which requires measurement of minimum and maximum diameter of the machined tube;
2. Curvature of tube's longitudinal axis, which generally is how much tube's axis differs from straight line;

Does anyone have an idea how to measure these parameters from deformed mesh using Abaqus/Visualization module or 3rd party software/algorithm? Or maybe what additional options should I include in model to get these outputs. The undeformed mesh is quite regular, due to simple shape of a workpiece, and nodes of each circular cross sections lie in the same plane, but after treatment nodes can be shifted both in radial and axial directions and no longer lie in the same plane.

Ideally the process should be possible to automate using Python scripting. The kinematics of process itself shouldn't be important, but if you are interested it is cross-roll straightening of a tube. The element type could be shell or 3D solid, it doesn't matter for now, the key is the principle of measurement.

Thanks in advance!

 

[FEA way]

There are no special tools for that but you could request the coordinates (COORD output variable) of the selected nodes and then use them for calculations. Of course, it can be done with Python scripting as well.

 

[simulation_engineer_2022]

FEA way, thank you for quick reply!

I guess the problem is more complex. I can get nodes coordinates by many ways, and in my opinion after that the tricky part begins. For example I have set of nodes which belonged to circular plane cross section before deformation. After deformation these nodes got displacements in arbitrary directions, for example in tube's longitudinal direction, because tube's segments can stretch and shorten during processing operation. So nodes are no longer in one plane but still belong to tube's surface. How to measure diameter of this cross section? Or how to measure diameter of any other sections? I understand that this is not particularly Abaqus problem, but I suppose it is connected to FEA simulations in general.

I've attached approximate nodes shifting scheme for clarity.

Best regards!

 

[FEA way]

This would likely require some external postprocessing tool like Matlab. I did something similar (but only for visual check) here:

https://www.eng-tips.com/viewthread.cfm?qid=453873

Once you have the coordinates of all the nodes that used to form a circular cross-section, you could connect them with edges and generate a surface to be further analyzed. Even FreeCAD might be enough to do this since it can handle point clouds.