بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ

In the name of Allah, the Compassionate, the Merciful

@modelscript/fea

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

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Core Capabilities

• Multi-Dialect FEA Solver Deck DSL (.fea, .inp, .inpt, .bdf): Declarative grammar (feaLanguage) and dialect parsers supporting CalculiX / Abaqus keyword cards (*NODE, *ELEMENT, *NSET, *ELSET, *MATERIAL, *ELASTIC, *DENSITY, *SOLID SECTION, *BOUNDARY, *CLOAD, *DLOAD, *STEP) via InpDialect and NASTRAN 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/Abaqus (*BOUNDARY, *CLOAD, *DLOAD) or NASTRAN (SPC1, FORCE, MOMENT) cards, and injects them before *END STEP or ENDDATA via applyBoundaryActionToDeck.
• 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.

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Package Structure

Path	Description
src/index.ts	Public package exports (feaLanguage, materializeFeaDeck, synthesizeFeaBoundary, parseInpDeck, dialects)
src/language.ts	Grammar definition, LSP actions (open_fea_viewer, materialize_deck, run_simulation), and 6 polyglot TGG rules
src/materializer.ts	evaluateFeaExpression, materializeFeaDeck, synthesizeFeaBoundary, applyBoundaryActionToDeck, and extractFeaSlicingProperties
src/types.ts	Core FEA model types (FeaModelData, FeaNode, FeaElement, FeaMaterial, BoundaryActionPayload, FeaDialect)
src/dialects/index.ts	Dialect registry (registerFeaDialect, getFeaDialect)
src/dialects/inp.ts	InpDialect parser and materializer for CalculiX / Abaqus .inp decks (parseInpDeck, materializeCalculixDeck)
src/dialects/bdf.ts	BdfDialect parser and materializer for NASTRAN .bdf Bulk Data decks

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Polyglot Triple Graph Grammar (TGG) Rules

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

Rule Name	Source (fea)	Target (modelica / sysml2)	Priority
FeaStressMassToModelicaParam	KeywordCard(name: "SOLID SECTION")	modelica: ComponentClause(name: "m", defaultValue: mass)	15
FeaStressMassToSysmlAttribute	KeywordCard(name: "SOLID SECTION")	sysml2: AttributeUsage(declaredName: "totalMass", defaultValue: mass)	15
FeaBoundaryFixToModelicaFixed	KeywordCard(name: "BOUNDARY")	modelica: ComponentClause(name: "fixedBoundary", typeSpecifier: "Modelica.Mechanics.Translational.Components.Fixed")	10
FeaSpringToModelicaSpring	KeywordCard(name: "SPRING")	modelica: ComponentClause(name: "springComponent", typeSpecifier: "Modelica.Mechanics.Translational.Components.Spring")	10
FeaMaterialToSysmlAttribute	KeywordCard(name: "MATERIAL")	sysml2: AttributeUsage(declaredName: "material", defaultValue: modulus)	5
FeaLoadCaseToSysmlRequirement	KeywordCard(name: "LOADCASE")	sysml2: ConstraintUsage(declaredName: "loadCase")	0

---

Scripts

Command	Description
npm run build	Compile TypeScript to dist/
npm test	Run unit and dialect test suites via test-runner.js
npm run lint	Run ESLint across src/ and tests/
npm run typecheck	Run tsc --noEmit type verification
npm run clean	Remove dist/ build artifacts

---

Programmatic Usage

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);