Finite Element Analysis (FEA) solver deck DSL supporting CalculiX- and Abaqus-compatible (.inp, .inpt), NASTRAN-compatible Bulk Data (.bdf), and .fea files, with a WebAssembly GLR parser, {{ expr }} parametric deck materializer, 3D CAD boundary/load card synthesizer, pre-flight structural linter (F1001–F1008 / M7401–M7408), structural theory slicer, and 3D Tet4/Tet10 FEA solver integration.

• Multi-Dialect FEA Solver Deck DSL (.fea, .inp, .inpt, .bdf): Declarative grammar (feaLanguage) and dialect parsers supporting CalculiX- and Abaqus-compatible keyword cards (*NODE, *ELEMENT, *NSET, *ELSET, *MATERIAL, *ELASTIC, *DENSITY, *SOLID SECTION, *BOUNDARY, *CLOAD, *DLOAD, *STEP) via InpDialect and NASTRAN-compatible Bulk Data cards (GRID, CTETRA, CHEXA, PSOLID, MAT1, SPC1, FORCE, MOMENT, ENDDATA) via BdfDialect.
• WASM GLR Incremental Parser: Built on @modelscript/dsl (language()), indexing FeaDeck, KeywordCard, and EmbeddedExpression symbols with Salsa query hooks (instantiate, resolveSimpleName).
• {{ expr }} Parametric Deck Materializer (materializeFeaDeck): Evaluates embedded expressions ({{ ... }}) inside .inpt parametric templates against a safe mathematical function library (sin, cos, sind, cosd, sqrt, cbrt, pow, PI, etc.) and external parameter tables (evaluateFeaExpression, materializeCalculixDeck), reporting precise 1-indexed line and column diagnostics on unresolved parameters.
• 3D Face Boundary & Load Card Synthesizer (synthesizeFeaBoundary): Translates interactive 3D CAD face/node selections (BoundaryActionPayload for fix, displacement, force, moment, and pressure) into CalculiX- and Abaqus-compatible (*BOUNDARY, *CLOAD, *DLOAD) or NASTRAN-compatible (SPC1, FORCE, MOMENT) cards, and injects them before *END STEP or ENDDATA via applyBoundaryActionToDeck.
• Pre-Flight Structural Linter (lintFeaModel, FeaErrorCode): Validates elastic modulus positivity, Poisson's ratio physical stability bounds ($-1.0 < \nu < 0.5$), rigid-body boundary constraints, non-empty meshes, material assignments, degenerate element nodes, yield strength, and mass density with Quick-Fix actions.
• Structural Theory Slicing (extractFeaSlicingProperties): Extracts reduced-order structural bounding scalars—total mass ($m$), maximum von Mises stress ($\sigma_{\text{max}}$), material yield strength ($\sigma_y$), safety factor ($\text{SF} = \sigma_y / \sigma_{\text{max}}$), and safety predicate (isSafe)—for continuous 1D DAE co-simulation and formal contract verification.
• Built-in 3D Tet4/Tet10 FEA Solver Integration: Parses 3D tetrahedral (C3D4, C3D10, CTETRA) and hexahedral (C3D8, C3D8R, CHEXA) meshes, node sets, isotropic material properties ($E, \nu, \rho$), Dirichlet boundary fixities, and concentrated nodal loads into FeaModelData for direct execution on @modelscript/simulate's 3D finite element structural solver (run_simulation, open_fea_viewer).
• Bidirectional Polyglot TGG Rules: 6 Triple Graph Grammar (TGG) rules linking FEA sections, materials, boundary conditions, springs, and load cases with Modelica mechanics components and SysML v2 requirements/attributes.

@modelscript/fea defines 6 bidirectional TGG rules in feaLanguage.polyglot.rules:

# Inspect FEA mesh nodes, elements, materials, and boundary conditions
msx fea inspect cantilever.inp

# Run pre-flight structural lint checks (F1001–F1008)
msx fea lint cantilever.inp

# Solve 3D structural displacements, von Mises stress, and safety factor
msx fea solve cantilever.inp

# Project FEA structural deck to Modelica or DAE JSON
msx fea to-modelica cantilever.inp --out=CantileverBeam.mo
msx fea to-dae cantilever.inp --out=cantilever-dae.json

import {
  applyBoundaryActionToDeck,
  extractFeaSlicingProperties,
  materializeFeaDeck,
  parseInpDeck,
} from "@modelscript/fea";

// 1. Materialize a parametric CalculiX template (.inpt -> .inp)
const template = `
*HEADING
Parametric Cantilever Beam
*NODE
1, 0.0, 0.0, 0.0
2, {{ beam_length }}, 0.0, 0.0
*MATERIAL, NAME=AL7075
*ELASTIC
{{ youngs_modulus }}, 0.33
*DENSITY
{{ density }}
*STEP
*STATIC
*END STEP
`;

const inpDeck = materializeFeaDeck(template, {
  evaluator: { beam_length: 0.25, youngs_modulus: 7.17e10, density: 2810.0 },
});

// 2. Synthesize & inject 3D boundary fixity and tip load cards before *END STEP
const withFix = applyBoundaryActionToDeck(inpDeck, { kind: "fix", targetId: 1, dofs: [1, 2, 3] }, "calculix");
const withLoad = applyBoundaryActionToDeck(withFix, { kind: "force", targetId: 2, vector: [0, 0, -500] }, "calculix");

// 3. Parse mesh topology and extract structural slicing properties
const model = parseInpDeck(withLoad);
const slicing = extractFeaSlicingProperties(withLoad);
console.log(model.nodes.size, slicing.safetyFactor, slicing.isSafe);

CalculiX, Abaqus, NASTRAN, and all other third-party software marks referenced herein are trademarks or registered trademarks of their respective owners (including Dassault Systèmes Simulia Corp., NASA, and MSC Software / Hexagon AB). Reference to these marks is strictly for nominative identification of input deck compatibility, syntax parsing, and data interchange. ModelScript is an independent open-core project and is not affiliated with, endorsed by, or sponsored by these entities.