Radial constraint

[cqf_2232]

Dear STKO Team，
I want to simulate the corrosion expansion effect of steel bars. The expansion of corrosion products is simulated by applying radial displacement or radial force to the concrete circular hole. How to apply this radial constraint in STKO?

[STKO Team]

You can, by using the Local coordinate system, and Function option if the pressure value depends on the spatial coordinates (x,y,z)

pressure_const.png (150.49 KiB) Viewed 2576 times

pressure_function.png (165.62 KiB) Viewed 2576 times

[cqf_2232]

Thanks for your prompt reply. If the concrete is a 3D solid, should I apply the load with Faceforce or SurfaceLoad? Also, I see that the displacement loading (sp) is a single point constraint, so how is the radial displacement applied?

[STKO Team]

If the concrete is a 3D solid, should I apply the load with Faceforce or SurfaceLoad?

FaceForce is the correct one. SurfaceLoad is for simulating floor loads when slabs are not modeled.
In the case of FaceForce, of course, you should use "Local" and use the "Z" component of the load, which is always normal to the face.

Also, I see that the displacement loading (sp) is a single point constraint, so how is the radial displacement applied?

It is a single point constraint, but is considered as a load in OpenSees, so it goes into a LoadPattern, with an associated timeSeries as any other load.

However, with the imposed displacement you cannot use the "Local" feature. So you should apply an Sp (with a function) for each component of your normal vector.

However, in your picture, it speaks about a "pressure" so the faceforce should be fine