A cantilever beam, from geometry to solver input

The smallest structural model there is: a beam fixed at one end and loaded at the other. This tutorial takes it from an empty viewer to a Kratos MDPA file with the two regions a solver needs — where it is clamped and where the load goes — and a handoff manifest that proves what was exported.

It is deliberately tiny so the numbers are checkable by hand. It takes about 10 minutes.

Starting point

Open examples/STP/block.stp (the seed block described in the overview).

Step 1 — Add the beam

In the Edits panel add a Box with centre 0, 0, 0 and size 100, 10, 10. It fully encloses the seed block, which stays behind as solid-0; the beam is solid-1.

[
  { "op": "addBox", "center": [0, 0, 0], "size": [100, 10, 10] }
]

Check it in the Mass Properties panel: select solid-1 and read a volume of exactly 10000 mm³ (100 × 10 × 10). For a mass as well, give a part containing it a density — see Step 3.

Step 2 — Name the two regions

1. Select ▾ → Selection mode → Surf, then click the beam's end face at x = −50.
2. In the Parts panel click ＋ New, rename it FixedEnd, and click ＋ on its row.
3. Repeat for the end face at x = +50, naming it LoadFace.

Headless, the same thing is two set_part calls (surfaces with the face ids that inspect reports with normals −X and +X).

Step 3 — Optional: a material

Make a part containing the beam (solid-1, assigned with Volume selection), and type 7.85 into its density field (or call set_part with volumes: ["solid-1"] and material: "steel"). The BOM now reports the beam's mass: 10 cm³ × 7.85 g/cm³ = 78.5 g.

Step 4 — Mesh and export

In the FE Mesh panel keep Dimension at 3, set Size max to 5, press Generate, then export Kratos MDPA — Elements + Conditions. Turn on the handoff manifest if you want a checksummed record of the export.

In the .mdpa, both parts appear as sub-model-parts:

Begin SubModelPart FixedEnd
    Begin SubModelPartNodes

Every node listed under FixedEnd has x = −50 exactly, and every LoadFace node x = +50 — the regions are on the faces you picked, not near them.

What you practiced

• Building a part whose answer you can check by hand (a 10 000 mm³ beam).
• Naming boundary-condition regions as parts, and seeing them arrive as SubModelParts.
• Material density and mass.
• The handoff manifest.

Next: the longer FEA preparation tutorial adds per-part mesh sizing and the quality summary.