# Femis

> >-

- **Type:** Skill
- **Install:** `agentstack add skill-test1card-femis-skill-femis-skill`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [test1card](https://agentstack.voostack.com/s/test1card)
- **Installs:** 0
- **Category:** [AI & ML](https://agentstack.voostack.com/c/ai-and-ml)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [test1card](https://github.com/test1card)
- **Source:** https://github.com/test1card/femis-skill
- **Website:** https://github.com/test1card/femis-skill

## Install

```sh
agentstack add skill-test1card-femis-skill-femis-skill
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# FEM / CAE — structural · thermal · CFD · multiphysics

> **This skill governs engineering claims — it does not drive solvers or sign off designs.** It pairs with a
> solver driver / MCP (PyMAPDL, PyMechanical, an Abaqus / OpenFOAM driver, OASiS, a CAE MCP) that
> *executes*; this skill decides **whether a result may be claimed, at what altitude, and when a human must
> decide.**

## Overview

Govern finite-element and CAE analysis end-to-end. **Paired with an executor** (PyMAPDL, PyMechanical,
PyFluent, an Abaqus/OpenFOAM driver, a CAE MCP — see "governance layer, not the executor" below) the *executor*
locates the installed solver, builds the deck/script, and launches **headless/batch**; **this skill** guides and
audits the idealization, reads the log for convergence, inspects/parses results, and enforces professional practice
(idealization → meshing → connections → solve controls → convergence → mesh independence → V&V) on every run. The **methodology is solver-agnostic**; worked depth here is Ansys / Simcenter / Thermal Desktop, with
breadth across Abaqus, LS-DYNA, MSC/Simcenter Nastran, COMSOL, OpenFOAM, Fluent, CFX, STAR-CCM+, CalculiX,
Code_Aster (see `references/software-landscape.md`).

**Core principles (enforce as gates):**
1. **No result is trusted until its discretization (mesh/time-step) error is addressed** — *bounded and stated* in ENGINEERING (e.g. last-refinement QoI change, or a single-mesh ZZ/SPR estimate), *fully demonstrated* with a GCI study in the asymptotic range for SIGNOFF; a single-mesh number reported without any error statement is never a result. Plus the convergence checks below.
2. **Converge the Quantity of Interest (QoI), not the peak** — peaks at sharp corners/point loads/crack tips are singularities that never converge.
3. **Most error is born in pre-processing** (idealization, BCs, connections) — front-load those decisions.
4. **Verification before validation; calibration ≠ validation** — and an agent must not claim sign-off without run evidence.

**This SKILL.md is the router.** Depth lives in `references/` — load a reference only when its topic is in play.

## When to use

- Structural (static/modal/buckling/nonlinear/explicit), thermal (steady/transient/radiation), **CFD** (RANS/LES, CHT), **electromagnetics** (low-/high-frequency), **vibro-acoustics/NVH**, **multibody**, and **coupled multiphysics** (thermo-mechanical, FSI, EM-thermal).
- **Failure & durability:** fracture / damage-tolerance, fatigue (incl. vibration/spectral), composites, plasticity / shakedown / ratcheting, buckling & stability, crash / impact / drop.
- Contact, thermal contact resistance, bolted/welded/rigid connections; meshing & mesh-independence (GCI); element/solver/unit selection.
- Headless/batch solving and result parsing; optimization, calibration, inverse parameter ID / model updating.
- V&V / UQ; substructuring / ROM; cryogenic / vacuum / spacecraft thermal.
- Deciding **what an agent can automate headless vs what a human must do** (next section).

**Not for:** pure CAD modeling or problems better served by a closed-form hand calc.

## ★ Agent capability & headless-vs-human contract

Precisely who does what. Buckets: **AGENT-HEADLESS** (fully scriptable/batch, no GUI) · **AGENT-VIA-API** (Python/journal API, needs a session + license) · **HUMAN-GUI** (must be interactive at least once) · **HUMAN-JUDGMENT** (engineering decision the agent must not make alone) · **LICENSE-GATED**. Full per-platform detail: `references/agent-automation-boundary.md`.

| Operation | Classification | How / why |
|---|---|---|
| CAD import | AGENT-VIA-API | PyMAPDL/PyMechanical/`run_journal` import STEP/Parasolid |
| Geometry cleanup / heavy defeature | AGENT-VIA-API + HUMAN-JUDGMENT | scriptable defeature/pinch; messy repair + *what to defeature* is judgment |
| Meshing | AGENT-HEADLESS (Ansys) · SEED-IN-GUI (NX) | PyMAPDL/PyMechanical mesh fully headless; **NX `.fem`/`.sim` templates don't resolve in batch → seed once in GUI** |
| Material create/assign | AGENT-HEADLESS | scriptable on all platforms; supply T-dependent data |
| Contacts / connections | AGENT-HEADLESS (build) + HUMAN-JUDGMENT (type) | defining is scriptable; **bonded vs frictional / RBE2 vs RBE3 is an engineering choice** |
| BCs & loads | AGENT-HEADLESS | scriptable; agent must not invent the load case |
| Expose params for optimization | AGENT-HEADLESS (PyMAPDL `*SET`) · HUMAN-GUI (Workbench `P#`, NX Expressions, HEEDS tags) | only PyMAPDL is GUI-free for parameterization |
| Solve (steady/transient/nonlinear) | AGENT-HEADLESS + LICENSE-GATED | `ansys -b`, `nastran.exe`, `tmgnx`, `abaqus job=`, `fluent -g`, OpenFOAM, `cfx5solve -batch`, `starccm+ -batch` |
| Electromagnetic solve (machines/RF/eddy) | AGENT-VIA-API + LICENSE-GATED | **PyAEDT** (`import ansys.aedt.core`, `non_graphical=True`), COMSOL/getDP batch; ports/excitations/sweeps are engineering setup |
| Optimization / DOE / calibration | AGENT-HEADLESS (PyMAPDL+SciPy, optiSLang `-b`, HEEDS CLI) + GUI-AUTHOR-ONCE | author the study/tags in GUI once, then run headless |
| Results extraction | AGENT-HEADLESS | PyDPF, pyNastran (`.op2`/`.f06`), `.odb`, SINDA `.out`, CGNS/VTK |
| Post images/plots | AGENT-HEADLESS | pyvista off-screen, ParaView `pvbatch` |
| Correlation / model-update (MAC, node pairing) | HUMAN-GUI | interactive test↔analysis node pairing is GUI work |
| Template / `.sim` / project authoring (NX) | HUMAN-GUI | template registry not initialized headless → pre-create a seed, then drive it |
| Licensing | LICENSE-GATED | each parallel solver instance consumes its own seat |

**An agent must NEVER auto-do:** choose idealization / element / contact-type / BC alone (HUMAN-JUDGMENT) · accept a calibration knob **pinned at its physical-corridor edge** · report a **singular peak** or an **unconverged** result as a result · claim verification / mesh-independence / sign-off **without the run evidence** · perform an irreversible push/overwrite without authorization.

## Pairing & executor contract

This skill is the **governance layer, not the executor.** Pair it with whatever drives the solver (PyMAPDL,
PyMechanical, an Abaqus / OpenFOAM driver, OASiS, a CAE MCP): **the executor runs; this skill governs
the claim.** Trust no solver output without provenance — a result is creditable only when the executor returns:

- **Run manifest** (`run_manifest.json`, template `scripts/run_manifest_template.json`) — the traceability spine (NAFEMS R0033).
- **Solver name + exact version** — read from the *detected* install's banner/`-help`, never assumed.
- **Input-deck hash + result-file hash** (e.g. SHA-256 of the `.inp`/`.dat`/`.cdb` and of the `.rst`/`.rth`/`.op2`) — ties a number to the exact deck and result that produced it.
- **Command + flag evidence** — the actual launch line, flags verified against that version (version-aligned-commands rule, Step 0).
- **Isolated workspace** — a clean working dir; outputs written there, never overwriting a prior "final" without a `superseded_by` pointer.

A result lacking this provenance is a SMOKE/DEBUG artifact at best — phrase it as such (`references/claim-templates.md`).

## Execution modes (pick one per task — sets the mandatory gates and what you may claim)

| Mode | Use when | Mandatory gates | Never |
|---|---|---|---|
| **SMOKE** | prove env/deck/solve/parse runs | Step 0; solve completes; result file written **and** readable | claim any engineering number; tune anything |
| **DEBUG** | find a failure's cause | the **one decisive test** for the symptom; connectivity gate if thermal | present a diagnostic solve as a result |
| **ENGINEERING** | usable result + sanity checks | units; connectivity; reactions/heat/mass balance; convergence; QoI extraction; singularity check | claim sign-off; report a singular peak |
| **SIGNOFF** | defensible deliverable | all ENGINEERING **+ mesh & time-step independence (GCI, asymptotic range)** + traceable report + error bounds | skip any gate; hand-wave uncertainty |

A SMOKE/DEBUG result is a pipeline/physics check, **never** an engineering conclusion — label it.

## ★ Pre-claim self-check — answer ALL before stating any engineering number

This is the gate that makes the skill trustworthy. **Before you type a stress, temperature, frequency, margin,
drag, or "it passes,"** answer these. If any answer is *no / unknown*, you do **not** have a result — you have
a SMOKE/DEBUG output: say so and stop.

1. **Mode?** Which execution mode am I in, and have *its* mandatory gates passed? (SMOKE/DEBUG ⇒ not an engineering conclusion.)
2. **Units?** Consistent system verified (1g-mass / hand-calc check); density not unit-corrupt?
3. **Discretization error addressed?** Mesh **and** time-step error bounded *and stated* (GCI for SIGNOFF; single-mesh ZZ/SPR estimate for ENGINEERING)? A lone single-mesh number is never a result.
4. **Singularity excluded?** Is the QoI at a corner / point-load / crack-tip artifact? Read away or linearize before quoting.
5. **Balance checked?** Reaction = applied; heat/mass/energy balance within tolerance; convergence from the *residual history*, not the exit code?
6. **Allowable named?** Is there a margin vs a NAMED criterion / design code — not a bare number?
7. **Human-judgment gate crossed?** Did I silently choose a load case, contact type, allowable, defeature, or sign-off? If yes — **STOP and escalate** (`references/escalation-examples.md`).

Then phrase the result with the matching template in `references/claim-templates.md`. **The agent never claims
sign-off without run evidence, and never self-authorizes an engineering decision.** Exact solver flags / API
calls are themselves a claim — confirm them per the version-aligned-commands rule in Step 0.

## Step 0 — ALWAYS first: environment discovery

Never assume a version or path. Find what's installed/licensed, then confirm platform + physics + QoI.

```powershell
Get-ChildItem "C:\Program Files\ANSYS Inc" -Recurse -Filter "ANSYS*.exe" -ErrorAction SilentlyContinue | Select FullName   # MAPDL/Mechanical/Fluent/CFX
Get-ChildItem "C:\Program Files\Siemens" -Recurse -Include "nastran.exe","run_journal.exe","tmgnx.cmd","ugraf.exe" -ErrorAction SilentlyContinue
Get-ChildItem "C:\Program Files" -Recurse -Filter "abq*.bat" -ErrorAction SilentlyContinue   # Abaqus; also `which icem`, OpenFOAM `foamVersion`
$env:ANSYSLMD_LICENSE_FILE; $env:LM_LICENSE_FILE
(Get-CimInstance Win32_Processor | Measure-Object NumberOfCores -Sum).Sum   # PHYSICAL cores
```

Linux: `ansysNNN -b`, `nastran`, `abaqus`, `simpleFoam`, `fluent -g`; check `$LM_LICENSE_FILE`, `nproc`.

**Version-aligned commands (rule):** never emit a solver command, flag, or API call you have not verified exists in the **detected** release — versions rename flags and drift APIs. Confirm against the installed version's `-help`/docs before relying on it, especially for ENGINEERING/SIGNOFF.

## Canonical workflow (run in order)

1. **Objective + QoI** — the scalar that drives the decision (margin, deflection, frequency, peak T, drag). Not "run the model."
2. **Analysis type** — static/modal/buckling/thermal/CFD/coupled; linear vs nonlinear (material? large-deflection? contact? turbulence?).
3. **Idealize** *(most consequential)* — 1D/2D/3D; symmetry only if geometry **and** loads **and** BCs are symmetric; defeature irrelevant features. → `references/meshing-convergence.md`.
4. **Materials** — correct constitutive model; **temperature-dependent properties**; at cryo use **∫α(T)dT**. → `references/material-modeling.md`.
5. **Mesh** — element order/family, refinement at concentrations, quality gate. → `references/meshing-convergence.md`.
6. **Connections & contact**. → `references/mechanical-connections.md`, `references/thermal-contact-resistance.md`.
7. **BCs & loads** — remove only the rigid-body modes appropriate to the model's dimensionality/type (an unconstrained **3D solid** has 6; 2D, axisymmetric, shell-only and cyclic-symmetric models differ); loads over realistic areas (never point loads/constraints → singularities); inertia relief for free bodies. → `references/advanced-methods.md`.
8. **Solve controls** — solver type, cores, substeps + tolerances. → `references/solver-numerics.md`.
9. **Verify** — equilibrium, mesh/time-step independence, convergence history. → `references/vv-uq.md`.
10. **Validate** — vs test / hand-calc / NAFEMS benchmark (calibration ≠ validation).
11. **Post & report** — right measure, averaged-vs-unaveraged check, margins, stated assumptions.

## Consistent units (pick ONE system; solvers are unit-free)

| System | Length | Force | Stress/E | Mass | Density (steel) | g |
|---|---|---|---|---|---|---|
| **SI (m)** | m | N | Pa | kg | 7850 kg/m³ | 9.81 m/s² |
| **mm-t-s (common CAE)** | mm | N | MPa | tonne | **7.85e-9 t/mm³** | **9810 mm/s²** |

**Density is the silent corruptor:** wrong-unit density passes statics but wrecks every dynamic/explicit/transient-thermal result. MAPDL `/UNITS` is metadata only. Verify with a 1g mass check or a hand-calc natural frequency.

## Element selection & mesh quality (depth: `references/meshing-convergence.md`)

- **Quadratic** (mid-side nodes) for stress/curved geometry, esp. tets — **avoid linear TET4 for stress** (constant-strain → over-stiff, slow stress convergence; acceptable only as filler well away from the QoI). Linear for explicit/large-deformation. (*Shear locking* proper afflicts **fully-integrated linear** quads/hexes in bending — parasitic shear; fix with reduced integration, incompatible modes, or quadratic — not the same defect as TET4's constant-strain stiffness.) Modern quadratic solids resolve *mild* bending with ~1 element through thickness as a starting point (curvature-driven — confirm by convergence); **linear** elements need several, and accuracy-critical bending wants ≥2 quadratic.
- **Shell** if thickness/length ≲ 1/10–1/20; solid for 3D stress/through-thickness; beam for slender. Account for shell/beam **offsets** (they induce real moments).
- **Locking/hourglass:** linear full-integration shear-locks (~+34% stiffer in the standard bending test — magnitude problem-dependent); linear reduced-integration hourglasses (over-soft, needs control); use quadratic / enhanced-strain / B-bar / mixed u–P (near-incompressible).
- **Quality gate (before solving) — thresholds depend on physics:** **structural FEA** prioritizes Jacobian (negative = fatal), skewness, and aspect ratio (high aspect is often fine for bending/shells); **CFD** is far stricter on orthogonal quality (>0.2, near-wall), skewness (reject >0.95), and growth ratio (≤1.2–1.5). Common starting guide: skewness ≤0.5 · orthogonal quality >0.2 · Jacobian 1–10 · aspect ratio  SMP for scaling (small models saturate ~4–8 cores; >4 needs HPC packs). **Direct sparse** for ill-conditioned/nonlinear/modal (keep in-core; out-of-core ~10× slower); **iterative PCG** for large well-conditioned 3D solids (don't loosen tolerance to force convergence — fix the model).
- **Nonlinear:** read the **residual history, never the exit code**; Newton-Raphson (+ line search); **arc-length/Riks** for snap-through; auto-time-step + bisection; converge force+displacement (energy). Decode pivots: negative/zero = singular (under-constraint/lost contact/bad props).
- **Time integration:** implicit Newmark/HHT-α (unconditional) for dynamics; explicit central-difference (**Δt≤L_min/c**, mass-scaling 4. |
| "Converged" by exit code / CFD residuals only | Read residual history; monitor integrated quantities + imbalance. |
| Perfect/bonded thermal contact in vacuum/cryo | Use finite h_c. |
| Reusing structural contacts in a thermal solve | `CONTA174 KEYOPT(1)=0` → zero conduction; author fresh. |
| RBE2 everywhere | Over-stiffens — RBE3 to spread load without stiffness. |
| Forgetting CTE in thermal stress | Define `ALPX`/`A`+`TREF` or thermal stress is silently zero. |
| Engineering (not true) stress–strain in plasticity | Convert; extend past UTS via a hardening law, n

…

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [test1card](https://github.com/test1card)
- **Source:** [test1card/femis-skill](https://github.com/test1card/femis-skill)
- **License:** Apache-2.0
- **Homepage:** https://github.com/test1card/femis-skill

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-test1card-femis-skill-femis-skill
- Seller: https://agentstack.voostack.com/s/test1card
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.