3. Report structure and engineering standar

Report structure and engineering standards 学习卡片

An AI-generated CAE report is only useful if a reviewer can navigate it, verify it, and sign it off. That requires a stable document skeleton, an unbroken chain from every claim back to its source data, and explicit conformance to the standards the project has agreed to follow. This section defines a reference structure, shows how traceability is encoded in practice, and gives a compliance checklist that a technical reviewer can apply directly.

3.1 A Reference Section Skeleton

Most structural, thermal, and CFD deliverables converge on the same logical order: state the problem, state the assumptions, show the model, show the results, then interpret them. The table below is a working skeleton that maps each section to its engineering purpose and to the evidence a reviewer will look for.

Section Engineering purpose Reviewer evidence
1. Scope & objectives Define what is being qualified and to which criteria Load cases, acceptance thresholds, referenced spec IDs
2. Inputs & assumptions Freeze geometry revision, material data, boundary conditions CAD revision hash, material card source, BC table
3. Model description Document mesh, element types, contacts, solver settings Element count, min/max Jacobian, contact formulation
4. Verification Prove the model solves the intended equations Mesh convergence plot, energy balance, unit check
5. Results Present fields, histories, and extracted quantities Contour plots with legend ranges, probe tables
6. Validation & discussion Compare against test or hand calculation Correlation table, deviation percentage
7. Conclusions & margins State pass/fail and remaining margin Margin of safety, governing load case
8. References & approvals Close the audit trail Document IDs, revision, reviewer signature block

Two conventions matter more than the exact numbering. First, verification and validation must be separate sections: verification asks "did we solve the equations correctly," validation asks "did we solve the right equations." Merging them is the single most common structural defect in AI-drafted reports. Second, every numeric claim in Sections 5–7 must be reproducible from Sections 2–4 without opening the solver GUI.

3.2 Traceability as a Data Structure, Not a Paragraph

Traceability means that for any reported number you can walk backwards: result → extraction location → load case → boundary condition → material property → source document. In practice this is implemented with stable identifiers rather than prose. A workable scheme uses a requirement ID, a model entity ID, and a result ID, linked in a traceability matrix.

REQ-014  "Bracket shall survive 15 g lateral load, no yield"
  └─ LC-003   load case: 15 g lateral, +X, 0.1 s ramp
       └─ BC-021  fixed at 4 bolt holes, RBE2 to ref node 9001
            └─ MAT-007  Al 7075-T6, E=71.7 GPa, Sy=503 MPa (MMPDS-01)
                 └─ RES-112  max von Mises = 431 MPa @ node 24517, t=0.1 s
                      └─ MS = Sy/(SF*sigma) - 1 = 503/(1.5*431) - 1 = -0.22  FAIL

Note the margin-of-safety convention used here: MS = allowable / (SF × applied) − 1, so a negative value is a failure. Whatever convention is chosen, it must be stated once in Section 1 and used identically in every table and figure. Mixing MS = allowable/applied − 1 with a factored form in the same report is a compliance defect even when the numbers are individually correct.

When an AI assistant drafts the narrative, it should be constrained to emit these identifiers verbatim. A useful guardrail is to require that every sentence containing a number also contains at least one ID token matching the pattern (REQ|LC|BC|MAT|RES)-\d+. Sentences that fail this check are flagged for human completion rather than silently published.

Practical rule: if a figure cannot be regenerated from the IDs listed in its caption, it does not belong in the report. Captions should read like "Figure 7 — von Mises stress, LC-003, RES-112, legend 0–500 MPa, deformed scale 5×", not "stress results."

3.3 Compliance Requirements for Technical Review

Compliance is project-specific, but the categories are stable. A reviewer typically checks four families of requirements: document control (revision, approval, distribution), method compliance (solver version, element quality limits, convergence criteria), regulatory or contractual compliance (e.g., ASME BPVC Section VIII Div. 2 for pressure vessels, Eurocode 3 for steel structures, or a customer-specific stress report specification), and data integrity (units, significant figures, no orphaned results).

The following checklist is written so it can be pasted into a review record and marked pass/fail per line. It is deliberately short; a checklist that takes an hour to fill out will not be used.

# Check Acceptance criterion
C1 Units declared Single consistent system stated in Section 1; no mixed mm/MPa with N·m
C2 Solver and version recorded Exact version string, e.g. Abaqus 2023 HF3
C3 Mesh quality reported Min Jacobian, max aspect ratio, % elements above warning threshold
C4 Convergence demonstrated Residual or mesh-convergence curve with tolerance stated
C5 Traceability matrix complete Every REQ maps to ≥1 RES; no RES without a parent LC
C6 Margins recomputed independently Reviewer recalculates at least the governing MS by hand
C7 Assumptions bounded Each assumption has a stated validity range and a sensitivity note
C8 Approval block signed Author, checker, approver with dates and revision ID

3.4 Worked Example: Reviewing a Bracket Report

Consider a deliverable for a satellite equipment bracket. The AI draft reports a maximum von Mises stress of 431 MPa under a 15 g lateral load and concludes "margins are adequate." A reviewer applying the checklist finds three defects. C1 fails because the material card is in MPa but the load table is in g and the geometry in inches. C5 fails because RES-112 has no parent LC in the matrix — the 15 g case was added after the matrix was frozen. C6 fails because the reported margin used MS = 503/431 − 1 = +0.17, omitting the required safety factor of 1.5; the correct value is −0.22, a failure.

The corrective action is not to rewrite the prose. It is to fix the matrix, re-run the extraction with the correct factor, and regenerate the affected figures. This is exactly the workflow where AI assistance pays off: the narrative and tables can be regenerated automatically once the underlying IDs and factors are corrected, provided the report was authored against a structured data source rather than free text.

Common failure mode: an AI-drafted report that is internally consistent but externally non-compliant. It will pass a casual read because every number agrees with every other number. Only a checklist tied to the governing standard catches the missing safety factor or the unapproved solver version.

3.5 Encoding the Structure for Automated Generation

To make the skeleton machine-checkable, store it as a template with required fields rather than as a Word outline. A minimal JSON schema fragment for one result block looks like this:

{
  "result_id": "RES-112",
  "parent_load_case": "LC-003",
  "quantity": "von_Mises_stress",
  "extreme_value": 431.0,
  "units": "MPa",
  "location": {"node": 24517, "time_s": 0.1},
  "allowable": 503.0,
  "safety_factor": 1.5,
  "margin_of_safety": -0.22,
  "verdict": "FAIL",
  "figure_ref": "FIG-007"
}

With this schema, the compliance checks C1, C5, and C6 become automated assertions: units must be non-null, parent_load_case must resolve, and margin_of_safety must equal allowable/(safety_factor*extreme_value) − 1 within rounding tolerance. The AI layer then only writes connective prose, and the reviewer's effort shifts from arithmetic to engineering judgment — which is where it belongs.

Traceability Chain and Compliance Gates Each link must resolve before the next is trusted; gates C1–C8 are checked at review REQ-014 15 g lateral, no yield LC-003 +X, 0.1 s ramp BC-021 4 holes, RBE2 → 9001 MAT-007 Al 7075-T6, Sy 503 MPa RES-112 431 MPa @ node 24517 SF = 1.5 project requirement MS = −0.22 FAIL — no margin Compliance gates applied at review C1 units declared C2 solver version C3 mesh quality C4 convergence C5 matrix complete C6 MS recomputed C7 assumptions bounded C8 approval signed Red gates failed in the worked example: C5 (orphaned RES-112) and C6 (safety factor omitted). Corrective action: repair the matrix, re-extract with SF = 1.5, regenerate FIG-007 and the margin table.

The structure, the identifiers, and the gates are what make an AI-assisted report reviewable. Once they are in place, the reviewer's job is reduced to the two questions that actually require an engineer: are the assumptions defensible, and is the governing load case the right one?