FESADev/phases/linear-static-mitc4-shell/step4.md

Step 4: MITC4 Stiffness and Drilling Stabilization

담당 역할과 필수 스킬

• 담당 역할: implementation-agent
• 필수 스킬: harness, fesa-cpp-msvc-tdd

읽어야 할 파일

• /.agents/skills/harness/SKILL.md, /.codex/skills/fesa-cpp-msvc-tdd/SKILL.md
• /AGENTS.md, /docs/PRD.md, /docs/ARCHITECTURE.md, /docs/ADR.md
• /docs/HARNESS.md, /docs/HARNESS_WORKFLOW.md, /.codex/hooks.json
• /docs/linear-static-mitc4-shell/implementation-plan.md
• /docs/linear-static-mitc4-shell/requirements.md Requirements 031-038/050-056
• /docs/linear-static-mitc4-shell/research.md
• /docs/linear-static-mitc4-shell/formulation.md Sections 10-14, 17
• /docs/linear-static-mitc4-shell/numerical-review.md Sections 5.7, 6.1-6.2
• /docs/linear-static-mitc4-shell/io.md
• /docs/linear-static-mitc4-shell/reference-model.md
• phase indexes, step4.md, completed Step 3 kernel/header/test and summary

작업

1. MITC4-KERNEL-001..006를 production edit 전에 작성한다.
2. Common 2x2x2 integration으로 physical K20을 만들고 deterministic 20-to-24 congruence로 global-coordinate K24 physical을 만든다.
3. R+는 eight physical tangent-rotation diagonal의 finite positive values만 사용하고 k_ref=min(R+), k_d=1e-3*k_ref, K_drill=T_d^T(k_d I4)T_d를 정확히 구현한다.
4. Empty/nonfinite R+는 structured deterministic failure다.
5. Scaled symmetry <=1e-12, transform energy <=1e-12, physical rigid action <=1e-10, physical rank 14, stabilized rank 18/nullity 6, positive non-rigid energy, membrane/bending/shear/twist patch fields를 독립 test로 검증한다.

Acceptance Criteria

$requiredBuildPaths=@("C:/git/googletest","C:/Program Files (x86)/Intel/oneAPI/mkl/2026.1/lib/cmake/mkl","C:/Program Files (x86)/Intel/oneAPI/tbb/2023.1/lib/cmake/tbb","C:/Program Files/HDF_Group/HDF5/2.1.1/cmake")
foreach($p in $requiredBuildPaths){if(-not(Test-Path -LiteralPath $p)){throw "Missing $p"}}
cmake --fresh -S . -B .harness/build -G "Visual Studio 18 2026" -A x64 `
  "-DFESA_GTEST_SOURCE_DIR=C:/git/googletest" `
  "-DMKL_DIR=C:/Program Files (x86)/Intel/oneAPI/mkl/2026.1/lib/cmake/mkl" `
  "-DTBB_DIR=C:/Program Files (x86)/Intel/oneAPI/tbb/2023.1/lib/cmake/tbb" `
  "-DHDF5_DIR=C:/Program Files/HDF_Group/HDF5/2.1.1/cmake"
cmake --build .harness/build --config Debug --target fesa_unit_tests
ctest --test-dir .harness/build -C Debug -R "Mitc4ShellKernel|Mitc4ShellPatch|Mitc4ShellDrilling" --output-on-failure

Expected missing stiffness/drilling RED를 확인한 뒤 minimal GREEN. 이후:

cmake --build .harness/build --config Debug --target fesa_unit_tests
ctest --test-dir .harness/build -C Debug -R "Mitc4ShellKernel|Mitc4ShellPatch|Mitc4ShellDrilling|Mitc4ShellKinematics" --output-on-failure
cmake --build .harness/build --config Debug
ctest --test-dir .harness/build -C Debug --show-only=json-v1
ctest --test-dir .harness/build -C Debug --output-on-failure

검증 및 상태 갱신

RED/VERIFY evidence와 exact formula를 summary에 기록하고 현재 Step 상태만 갱신한다.

금지사항

• Translational diagonal을 R+에 넣지 마라.
• Coefficient sweep, calibration, drill energy/result, physical recovery를 구현하지 마라.
• S4R reduced integration/hourglass와 future nonlinear tangent를 구현하지 마라.
• 직접 commit/hook 실행 또는 reference/upstream 변경을 하지 마라.