Agent skill

freecad-automation-fem-chain-workflow

Sub-skill of freecad-automation: CalculiX FEM analysis chain — geometry creation via gmsh, INP export, ccx solve, and result extraction.

View SKILL.md on GitHub Repository
Stars 4
Forks 4

Install this agent skill to your Project

npx add-skill https://github.com/vamseeachanta/workspace-hub/tree/main/.claude/skills/_archive/engineering/cad/freecad-automation/fem-chain-workflow

SKILL.md

FEM Chain Workflow (CalculiX)

Overview

End-to-end structural FEM pipeline: gmsh geometry → INP file → CalculiX solve → stress/displacement extraction.

Pipeline Steps

  1. Create geometry — gmsh OCC kernel (plate-with-hole, STEP import, etc.)
  2. Define analysis — material, BCs, loads → INP file via INPWriter
  3. Solve — CalculiX ccx subprocess
  4. Extract results — parse .frd (nodal fields) and .dat (reactions)

Quick Start: Plate-with-Hole Validation

python
from digitalmodel.solvers.calculix.fem_chain import FEMChain

chain = FEMChain()
result = chain.run_plate_validation(sigma_applied=100.0)
print(f"Kt = {result['kt']:.3f}")  # ~3.0 within 5%

Custom Analysis

python
from pathlib import Path
from digitalmodel.solvers.calculix.fem_chain import FEMChain

chain = FEMChain(work_dir=Path("/tmp/my_fem"))

# 1. Create geometry (quarter-symmetry plate with hole)
stats = chain.create_plate_with_hole(
    plate_w=200.0, plate_h=200.0, hole_r=10.0,
    thickness=1.0, element_size=5.0,
)

# 2. Setup analysis
chain.setup_analysis(
    material={"name": "STEEL", "E": 210000.0, "nu": 0.3},
    loads=[{
        "type": "cload", "node_set": "LOAD",
        "dof": 1, "magnitude": 100.0, "direction": (1, 0, 0),
    }],
    boundary_conditions=[
        {"node_set": "SYM_X", "dof_start": 1, "dof_end": 1},
        {"node_set": "SYM_Y", "dof_start": 2, "dof_end": 2},
        {"node_set": "FIX_Z", "dof_start": 3, "dof_end": 3},
    ],
)

# 3. Solve
status = chain.solve()
assert status["success"]

# 4. Results
results = chain.extract_results()
print(f"Max von Mises: {results['max_von_mises']:.1f} MPa")
print(f"Max displacement: {results['max_displacement']:.6f} mm")

Key Classes

Class Module Purpose
FEMChain solvers.calculix.fem_chain End-to-end orchestrator
INPWriter solvers.calculix.inp_writer Mesh → INP file conversion
CalculiXResultParser solvers.calculix.result_parser .frd/.dat parsing
GMSHMeshGenerator solvers.gmsh_meshing.mesh_generator STEP import + meshing

Prerequisites

  • gmsh Python package (pip install gmsh)
  • ccx binary on PATH (CalculiX solver)
  • Check availability: from digitalmodel.solvers.calculix.fem_chain import is_calculix_available

Node Sets (Plate-with-Hole)

Set Description
SYM_X Nodes on x=0 symmetry plane
SYM_Y Nodes on y=0 symmetry plane
FIX_Z Nodes on z=0 face (out-of-plane constraint)
LOAD Nodes on far edge (x=W/2) for applied traction

Validated Results

  • Plate-with-hole Kt within 5% of theoretical 3.0 (d/W < 0.3)
  • Quarter-symmetry model with W/d > 5

Recommended Agent Skills

Expand your agent's capabilities with these related and highly-rated skills.

vamseeachanta/workspace-hub

gsd-complete-milestone

Archive completed milestone and prepare for next version

4 4
Explore
vamseeachanta/workspace-hub

gsd-reapply-patches

Reapply local modifications after a GSD update

4 4
Explore
vamseeachanta/workspace-hub

gsd-verify-work

Validate built features through conversational UAT

4 4
Explore
vamseeachanta/workspace-hub

gsd-thread

Manage persistent context threads for cross-session work

4 4
Explore
vamseeachanta/workspace-hub

clinical-trial-protocol

Generate clinical trial protocols for medical devices or drugs through a modular, waypoint-based architecture with research-only and full protocol modes.

4 4
Explore
vamseeachanta/workspace-hub

single-cell-rna-qc

Performs quality control on single-cell RNA-seq data (.h5ad or .h5 files) using scverse best practices with MAD-based filtering and comprehensive visualizations.

4 4
Explore

Didn't find tool you were looking for?

Be as detailed as possible for better results