Step 4: nonlinear-mitc4-residual-and-tangent

읽어야 할 파일

AGENTS.md
docs/ARCHITECTURE.md
docs/ADR.md
docs/nonlinear-static-newton-raphson/formulation.md
docs/nonlinear-static-newton-raphson/numerical-review.md
include/fesa/elements/nonlinear_mitc4_shell.h
src/fesa/elements/nonlinear_mitc4_shell.cpp
tests/unit/elements/nonlinear_mitc4_shell_test.cpp
Step 2 files: include/fesa/elements/finite_rotation.h
Step 3 files: include/fesa/elements/nonlinear_mitc4_shell.h

이전 Step 전제

Step 3 provides nonlinear MITC4 creation, kinematics, and recovery rows.

소유 파일

Modify: include/fesa/elements/nonlinear_mitc4_shell.h
Modify: src/fesa/elements/nonlinear_mitc4_shell.cpp
Create: tests/unit/elements/nonlinear_mitc4_shell_tangent_test.cpp
Modify: tests/CMakeLists.txt

인터페이스

namespace fesa {

struct NonlinearMitc4InternalEquilibrium {
  Vector internal_residual;
  Matrix internal_tangent;
  Vector internal_force;
  NonlinearMitc4Recovery recovery;
  double physical_strain_energy;
};

Result<NonlinearMitc4InternalEquilibrium> EvaluateInternalResidualAndTangent(
    const NonlinearMitc4Shell& element,
    const NonlinearMitc4TrialDofs& trial);

}  // namespace fesa

RED

Add tests first.

NSNR-ELEM-TAN-001: residual and tangent are evaluated at the same trial state.
NSNR-ELEM-TAN-002: directional derivative schedule uses h={1e-3,3e-4,1e-4,3e-5,1e-5,3e-6,1e-6,3e-7} and requires at least two observed orders >=1.5.
NSNR-ELEM-TAN-003: one interior scaled derivative error is <=1e-6.
NSNR-ELEM-TAN-004: zero analytical directions produce scaled absolute error <=1e-10.
NSNR-ELEM-TAN-005: no-moment tangent satisfies scaled Frobenius symmetry <=1e-12 after Dq^T K_T Dq.
NSNR-ELEM-TAN-006: internal tangent contains no external fixed-load contribution; applying the same element to two incident-element load-sharing scenarios does not change internal residual/tangent.
NSNR-ELEM-TAN-007: finite rigid motion keeps physical residual/objectivity invariants.
NSNR-ELEM-TAN-008: patch/sign recovery identities pass relative <=1e-9.
NSNR-ELEM-TAN-009: nonfinite trial/residual/tangent data fails closed.

Run:

cmake --build --preset windows-msvc-ninja-debug
ctest --preset windows-msvc-ninja-debug -R "NonlinearMitc4Residual|NonlinearMitc4Tangent|NonlinearMitc4Objectivity|NonlinearMitc4Patch" --output-on-failure

Expected: new tests fail. Unexpected pass stops.

GREEN

Implement same-trial internal residual/tangent, exact rotation derivative terms through J_l, map Hessian terms, objective drilling contribution, and physical recovery in the element-local contract. External CLOAD vector and tangent are not element inputs and are assembled globally in Step 5.

VERIFY

cmake --preset windows-msvc-ninja-debug
cmake --build --preset windows-msvc-ninja-debug
ctest --preset windows-msvc-ninja-debug -R "NonlinearMitc4Residual|NonlinearMitc4Tangent|NonlinearMitc4Objectivity|NonlinearMitc4Patch" --output-on-failure
ctest --preset windows-msvc-ninja-debug --show-only=json-v1
ctest --preset windows-msvc-ninja-debug --output-on-failure

Use the ignored .harness/config.json preset contract. The Harness process must inherit VsDevCmd x64 and FESA_GTEST_SOURCE_DIR, MKL_DIR, TBB_DIR, and HDF5_DIR from its parent launch environment.

상태 기록

Update only Step 4 status and one-line payload. Executor owns timestamps, commits, retry, and advancement.

금지사항

Do not symmetrize the internal tangent as a cleanup step. 이유: derivative and symmetry tests must observe the mathematically assembled operator; Step 5 owns external moment tangent nonsymmetry.
Do not add solver factorization in this Step. 이유: Step 6 owns tangent solver backend.
Do not pass nodal CLOAD force or moment into each incident element. 이유: it duplicates source-node loads; Step 5 owns global-once external assembly.
Do not claim Abaqus internal equivalence. 이유: FESA only uses Abaqus CSV as external numeric reference.

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