modify wiki

wiki/concepts/Finite Element Program Implementation.md

@@ -7,7 +7,7 @@ aliases:
   - finite element code architecture
   - STAP
 created: 2026-05-28
-updated: 2026-05-28
+updated: 2026-05-29
 address: c-000016
 tags:
   - concept
@@ -23,10 +23,21 @@ related:
   - "[[Dynamic Buckling Analysis]]"
   - "[[BLZPACK]]"
   - "[[ABAQUS]]"
+  - "[[Direct Stiffness Method]]"
+  - "[[Finite Element Modeling and Convergence Checks]]"
+  - "[[Abaqus Input File Syntax]]"
+  - "[[Abaqus Spatial Model Definition]]"
+  - "[[Abaqus Job Execution Workflow]]"
+  - "[[Abaqus Output Database and Results Files]]"
+  - "[[Abaqus Matrix Generation and Reduced Models]]"
+  - "[[Abaqus User Subroutines and Utility Routines]]"
 sources:
   - "[[Finite Element Procedures]]"
   - "[[Four-Node-Quadrilateral-Shell-Element-MITC4]]"
   - "[[Dynamic-Buckling-Analysis-of-Shell-Structures-using-Finite-Element-Method]]"
+  - "[[A-First-Course-in-the-Finite-Element-Method|A First Course in the Finite Element Method]]"
+  - "[[Abaqus-Analysis-User-s-Guide-Volume-I|Abaqus Analysis User's Guide Volume I]]"
+  - "[[Abaqus-Analysis-User-s-Guide-Volume-II|Abaqus Analysis User's Guide Volume II]]"
 ---
 
 # Finite Element Program Implementation
@@ -43,6 +54,12 @@ The MITC4 source adds a concrete code-level example: a shell element formulation
 
 The dynamic buckling thesis adds a second program implementation pattern: a custom MITC4 shell code uses a lumped mass matrix and [[BLZPACK]] for eigenvalue problems, then validates results against theoretical solutions, experiments, and [[ABAQUS]] comparisons.
 
+[[A-First-Course-in-the-Finite-Element-Method|A First Course in the Finite Element Method]] adds teaching-program examples: flowcharts and computer-assisted solutions for plane stress/strain, heat transfer, fluid flow, and structural dynamics show how element equations become reusable program workflows.
+
+[[Abaqus-Analysis-User-s-Guide-Volume-I|Abaqus Analysis User's Guide Volume I]] adds a production-code interface view: keyword input is parsed into model data and step history, nodes and elements become scoped spatial definitions, jobs are run through execution modes and environment settings, and results are written to databases, messages, status files, restart files, and selected results records.
+
+[[Abaqus-Analysis-User-s-Guide-Volume-II|Abaqus Analysis User's Guide Volume II]] adds the extension and reduction view: generated matrices, substructures, restart state, imported results, co-simulation exchange, and user subroutines are all implementation-facing boundaries where a finite element program exposes internal state or accepts external code.
+
 ## Why It Matters
 
 The finite element method becomes useful only when the mathematical formulation is encoded into reliable data structures and algorithms. Implementation details determine whether element routines, sparse matrix storage, solver selection, boundary condition handling, and postprocessing remain consistent.
@@ -50,15 +67,22 @@ The finite element method becomes useful only when the mathematical formulation
 ## Implementation Checklist
 
 - Define node, element, material, load, and boundary condition input structures.
+- Parse model data separately from step or history data.
 - Map local element degrees of freedom to global equation numbers.
 - Compute element matrices using shape functions, Jacobians, constitutive laws, and quadrature.
 - Assemble global sparse matrices and vectors.
 - Apply constraints and solve the resulting system.
 - Recover stresses or other derived quantities from the solved nodal field.
+- Write field output, history output, diagnostics, and restart data in formats the analyst can inspect.
+- Expose controlled extension points for user code, matrix exchange, restart, and solver coupling.
 - Verify new element implementations with patch tests and benchmark problems before treating production results as reliable.
+- Check mesh quality, convergence, and result interpretation before trusting a program output table.
 
 ## Sources
 
 - [[Finite Element Procedures]]
 - [[Four-Node-Quadrilateral-Shell-Element-MITC4]]
 - [[Dynamic-Buckling-Analysis-of-Shell-Structures-using-Finite-Element-Method]]
+- [[A-First-Course-in-the-Finite-Element-Method|A First Course in the Finite Element Method]]
+- [[Abaqus-Analysis-User-s-Guide-Volume-I|Abaqus Analysis User's Guide Volume I]]
+- [[Abaqus-Analysis-User-s-Guide-Volume-II|Abaqus Analysis User's Guide Volume II]]