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Verify · Design reassessment

High-fidelity reassessment: no design is recommended on a prediction alone

Optimisers are good at finding where a fast model is wrong, and the best design a surrogate predicts often sits exactly there. The TensorLynx platform puts a gate between the search and your design review: the recommendation is the best design the solver itself evaluated, predictions are held to solver values by rules written before any result exists, and a candidate is Verified only after an independent re-run.

Recommended = best solver-evaluated feasible designVerified only after an independent re-runUnknown is never a pass

Two candidate designs pass through five reassessment gates Candidate A passes the feasibility, surrogate-agreement, gradient, mesh and re-run gates and receives a Verified seal. Candidate B is stopped at the surrogate-agreement gate because the solver value falls outside the predicted band, and it is sent back to the optimiser. Schematic. PROPOSED RECOMMENDED optimiser FEASIBLE SURROGATE GRADIENT MESH RE-RUN sent back: solver outside the band A B INDEPENDENT RE-RUN · LIMITS SET FIRST · VERIFIED PASS: |Js − μ| ≤ 1.96σ and ≤ 2 % of |Js|
Candidate B stops at the surrogate gate; A earns the sealSchematic
The cost of the old way

The optimiser finds the model’s mistakes before you do

Every surrogate-based or low-fidelity search carries the same trap. The optimiser hunts for the lowest predicted value, and that value tends to sit where the model is most optimistic: at the edge of the design box, between sparse samples, outside its data. Trust-region model management has answered this since the late 1990s: an approximate step is checked against the high-fidelity model before it is accepted [3].

  • A promised gain that shrinks. The slide shows the model’s gain; the test bench shows the physics’.
  • Confident bands that are too narrow. An uncertainty estimate is a model too.
  • Checks nobody can find. A hand re-run, judged against a tolerance chosen after seeing the answer, does not survive a design review.

In a 2026 consultation for a NAFEMS and Teratec event on AI and simulation, 47 % of respondents named trust and validation of results among their top barriers Industry survey [1]. A 2026 survey of 120 manufacturers found that 16 % trust AI-supported verification and validation Industry survey [2].

Most simulation-AI pages lead with speed and rarely show the verification step. On the TensorLynx platform it is a stage of the loop, with its own rules, labels and report section.

A surrogate curve follows the true response where samples exist, then dips falsely in a region without data. The surrogate's predicted best design lies in that dip; the solver value there is much worse, and the true best design is elsewhere. no samples design variable objective (lower is better) predicted best what the solver says true best solversurrogate
Why the predicted best design needs a solver: the winner is often the model’s largest errorSchematic
How TensorLynx does it

Six steps from proposal to a design you can defend

Reassessment is where the loop stops trusting itself. Whatever produced the candidate, the same sequence applies, and each step leaves a label on screen and in the report.

01 · PROPOSE

The optimiser proposes

A gradient search, a surrogate-based search, a trust-region refinement or a point picked on the Pareto front ends with a candidate. Until something checks it, it is labelled what it is: Exploratory, not verified. The surrogate’s own pick gets no special status.

02 · EVALUATE

Only solver values count

The recommendation pool holds solver evaluations only. Failed or unconverged runs are never ranked, and are recorded as failed with outputs missing, never as zeros. Feasibility is judged on solver values against tolerances you declared. The recommended design is the best feasible, converged evaluation; when none exists, the run says Unconfirmed instead of choosing quietly.

03 · COMPARE

The prediction is held to the solver

Where a surrogate proposed the design, its prediction meets the solver value under a fixed rule: a pass needs a gap within 2 % and inside the 95 % band (±1.96σ); up to 5 % reads Caution, with the reason; beyond that, or without convergence, it fails Method. Only a pass earns “Surrogate-proposed design, confirmed by the solver”, and the reported value is always the solver’s. A surrogate that fails its own fit check has its prediction hidden.

04 · REJECT

A failed candidate goes back, with its reason

In a trust-region refinement, a step the solver does not bear out is not taken: the centre stays where the solver last stood and the region adapts to how well the model predicted. A step whose solve does not converge never becomes a centre. A predicted-feasible point the solver finds infeasible reads Infeasible, and its source stays “Prediction – not verified”. Nothing is averaged away.

05 · RE-RUN

An independent re-run earns “Verified”

Verify solves the chosen candidate again as a separate job, against your acceptance limits and a match tolerance you type in; there is no platform default. Only that re-run promotes a candidate to Verified, never an optimiser’s exit. In geometry-family studies the candidate is also re-solved on a finer mesh, with discretisation error from the Grid Convergence Index.

06 · RECORD

Recorded, then decided by a person

The study report carries “Verification evidence and limitations” next to the decision, and reports from the report library refuse export if a claim cannot be traced. Edit an acceptance limit later and old verdicts read Stale, keeping the limits they were judged by. The ranking is computed; a decision is recorded only when an engineer makes it, and the chain goes into the engineering record.

Reassessment bench. Left: candidates in the design space with a trust region. Right: the evidence for the current step: prediction, solver evaluation, prediction against solver value, rejection, independent re-run, and the report. 1 · The optimiser proposes 2 · Only solver values count 3 · Prediction against solver 4 · Step rejected, centre kept 5 · Independent re-run 6 · Recorded, then decided design space x* C A B PREDICTED Exploratory not verified μ ± 1.96σ, no solver value yet Aconverged · feasible RECOMMENDED x*converged · feasible ordinary candidate Cnot converged NEVER RANKED feasibility on solver values objective μ ± 1.96σ Js PASS gap ≤ 2 % and inside the band objective Js FAIL above 5 %: B is not taken runre-run Verified difference within your tolerance Study report Verification evidence and limitations Decision recorded by an engineer
Inside the engine

The rules behind each gate, written down before the results

The vocabulary follows ASME V&V 20 and 40, NASA-STD-7009B and NAFEMS [4–6]: credibility is evidence gathered for a stated use, and verification is not validation. Every verdict needs a rule, every rule a reference, and an unmeasured verdict reads Unknown.

Does the solver bear out the prediction?

r = |Js − μ| / |Js|

  • Pass: r ≤ 0.02 and |Js − μ| ≤ 1.96σ.
  • Caution: r ≤ 0.05 otherwise, naming a band too narrow or too wide; with no σ, capped at Caution.
  • Fail: r > 0.05, or the solve failed or did not converge.
  • Unknown: no prediction, or Js = 0.

Js: converged solver value; μ, σ: surrogate mean and standard deviation. Js is what is carried forward. Method

Solver-agreement rule on a number line around a prediction of 100: pass zone within 2 percent, caution zones up to 5 percent, fail beyond; the predicted band is drawn above, and a marker shows the chosen solver value. FAILCAUTIONPASSCAUTIONFAIL band μ ± 1.96σ 9095μ = 100105110 PASS · r = 0.0119, inside the band
Try the rule: the verdict is computed in your browser with the platform’s thresholdsMethod

Which design gets recommended?

  • Pool: evaluations with status OK, verdict “converged” and an objective present. Anything else is never ranked, never assumed converged.
  • Feasible: every constraint component inside [lower − t, upper + t] on solver values; an equality needs t > 0; missing feasibility is not feasible.
  • Pick: the best objective, ties to the lower evaluation number. The surrogate’s pick is an ordinary candidate.
  • Nothing feasible: nothing is recommended. The best predicted design is shown as Unconfirmed, with its band, and never selected.

Decisions are recorded by a person, append-only, superseded choices kept. Method

Was the search steered by a gradient that deserves it, on a mesh that resolves it?

  • Gradient: Taylor remainder and a directional finite-difference sweep over at least five decades of step, on two random seeds; usable below a relative error of 0.15. A pass reads “Direction-checked (usable for optimisation)”, never “verified”, and a failed check stays on the label. See gradient verification.
  • Mesh: Grid Convergence Index, safety factor 1.25 [7]: pass ≤ 5 %, Caution ≤ 10 %. An asymptotic ratio outside [0.9, 1.1] is flagged.
  • Missing is never zero: four passes and one unmeasured axis is not a pass.

Method

Can the result be produced again, and traced?

  • Verify: a separate job re-solves the candidate; Verified only if it meets your limits and matches within your tolerance. An unchecked match reads “Reproduction not checked”.
  • Run record: seeds, study-snapshot hash, model fingerprint, driver code hash, environment lock; absent, it reads “Reproducibility: MISSING (not recorded)”. Resume is refused if specification, seed or engine changed.
  • Report: HTML and JSON per study run. Report-library exports are refused for a claim without evidence, one citing an unknown provenance node, or no provenance store.

Method

Evidence you can check

Predictions that held, and the ones that were sent back

From TensorLynx study records: the band a surrogate predicted, next to the value the solver returned. Two held. Two were rejected as infeasible, and their source stayed a prediction.

Predicted bands against solver values for four recorded candidates, with each band normalised to the same width. Pipe bend, generated design: solver 7.8279 pascal inside the band 7.7326 to 7.8330. Pipe bend, refined design: solver 7.78317 pascal inside the band 7.7474 to 7.8385. Cantilever plate front point p1: solver tip displacement 18.47 millimetres, outside the band 3.44 to 16.55, infeasible. Cantilever plate front point P2: solver 16.61 millimetres, outside the band 2.84 to 13.15, infeasible. predicted band (±1.96σ), normalised per row bandpredicted meansolver value Pipe bend · generated designinside ✓ band 7.7326–7.8330 Pa · solver 7.8279 Pa Pipe bend · trust-region refinedinside ✓ band 7.7474–7.8385 Pa · solver 7.78317 Pa Plate · predicted front point p1infeasible ✕ tip band 3.44–16.55 mm · solver 18.47 mm Plate · predicted front point P2infeasible ✕ tip band 2.84–13.15 mm · solver 16.61 mm
Pipe-bend pressure loss (CFD) and cantilever-plate tip displacement (finite-element structural), recorded runs. The line marks the predicted mean.Measured

Promised against delivered

Pipe bend: the model promised +0.3726 Pa of pressure-loss reduction; the solver delivered +0.3275 Pa (4.0 % of baseline), inside the band, and that is the figure reported. After trust-region refinement the verified gain is +0.3722 Pa, 4.56 % of 8.1554 Pa, and the report labels its error budget unconfirmed, because mesh and turbulence-model error were outside the scope of this case. Measured · pipe bend

The surrogate’s pick lost to an evaluated design

Airfoil drag at fixed lift: the surrogate failed its fit check, so its prediction was hidden. The recommendation went to evaluation 24 (solver CD 0.019390, CL 0.50038), not the surrogate’s pick, evaluation 26 (CD 0.020652). Measured · recorded run

An independent re-run, to seven decimal places

Airfoil drag minimisation reproducing a published reference case, 4,032-cell study mesh: CD 0.0175321783 optimised, 0.0175321906 on re-run, relative difference 7.0e-7 against a 1e-4 tolerance: Verified. A plate-sizing re-run differed by 0 on mass, tip displacement and peak stresses. Measured

Solved again on a finer mesh

Bracket at constant volume: stress aggregate (KS of von Mises) 24.4 → 9.50 MPa (−61.1 %); the fine mesh confirmed −59.0 %; GCI 0.13 % over 1,635, 3,615 and 9,833 cells. S-duct intake: pressure drop 79.30 → 72.98 Pa (8.0 %), 8.9 % on a second mesh. Measured

4.56 %
verified pressure-loss reduction, solver value inside the predicted band Measured
−59.0 %
bracket stress aggregate, confirmed on the fine mesh Measured
0.13 %
Grid Convergence Index on the bracket’s three-mesh ladder Measured
2 of 4
predicted candidates above rejected by the solver and labelled Infeasible Measured
What it changes for your programme

A recommendation you can take into a design review

Simulation supports the decision; it does not replace your tests and sign-off. Reassessment changes what reaches them: designs the solver has confirmed, with the checks on record.

Engineering lead

One rule for what counts as recommended, in every study. A candidate that fails shows its reason before it reaches a review board.

Simulation analyst

No re-runs pasted into spreadsheets: Verify, the band check and the labels share the optimiser’s record, and failed checks stay attached.

Programme manager

Predicted and delivered gains side by side, so the gain in the plan is one the solver confirmed.

Aerospace

Drag at fixed lift: the surrogate proposes, solver evaluations recommend.

Automotive and structures

Brackets and plates re-solved on a finer mesh, discretisation error stated before release to test.

Turbomachinery, energy and process

Ducts, bends and intakes: promised and confirmed pressure-loss gains on one line.

Typical workflow compared with TensorLynx reassessment
QuestionTypical workflowWith TensorLynx
What is recommended?The optimiser’s final point, often a predictionThe best feasible, converged design the solver evaluated
Prediction vs solverChecked when someone remembers toA fixed rule: pass, caution or fail, with the reason
ToleranceChosen after the answer is knownDeclared by you up front; later edits mark verdicts Stale
A check not runSilently omittedUnknown, which is never a pass
“Verified”An adjectiveA status granted only by an independent re-run
The reportAssembled by handExported only if every claim traces to its evidence

Reassessment is one stage of the TensorLynx loop. OLTRION engineers agree limits and tolerances with you, run it on your designs and hand over the record.

FAQ

Questions engineers ask about reassessment

Is every optimised design re-run automatically on the full model?

The recommendation is always a design the solver itself evaluated: the best feasible, converged evaluation of the run. Verified status comes from a separate Verify step, launched by you or OLTRION engineers with your acceptance limits and match tolerance. Until then the candidate reads Exploratory.

What happens when a surrogate-optimised design fails reassessment?

It is not recommended, and the reason stays on the result. A solver value more than 5 % from the prediction, or a solve that does not converge, reads Fail. In a trust-region refinement the step is not taken and the centre stays where the solver last stood. A predicted-feasible point the solver finds infeasible is labelled Infeasible, and its source stays a prediction.

Does Verified mean the design is validated?

No. Verified means an independent re-run reproduced the candidate within your tolerance and met your acceptance limits: verification of the numbers, not validation of the physics against experiment. Simulation supports engineering decisions; it does not replace the tests and sign-off your programme requires.

Who sets the tolerances and acceptance limits?

You do, before the result exists; there is no default match tolerance. The platform's own verdict thresholds are written down with a reference before any measurement and never moved afterwards. Edit an acceptance limit later and earlier verdicts keep their original limits and read Stale.

What if a check could not be run?

It reads Unknown: not measured. Unknown is never a pass and never a failure, and four passes plus one unmeasured axis is not a pass. A missing value is never shown as zero.

How are reassessment results reported?

Each study run writes a self-contained HTML report and JSON, with a section on verification evidence and limitations next to the decision. Where a prediction is shown, it is labelled as one beside the solver value, and the value reported is the solver's. Reports from the report library refuse export when a claim cannot be traced to its evidence.

One loop, not twelve tools

Where high-fidelity reassessment sits in the TensorLynx loop

Every capability hands its result to the next on the same model, the same units and the same record: geometry feeds physics, physics feeds sensitivities and learning, optimisation proposes, verification confirms, and the history keeps every step reproducible.

The TensorLynx loop: Design exploration, Coupled multiphysics, Mesh verification, Adjoint optimisation, Gradient verification, Trust-aware surrogates, Full-field ROM, Multi-fidelity, MDAO, Pareto selection, High-fidelity reassessment, Provenance. TensorLynx one model · one record DefineSimulateImproveLearnOptimiseDecideVerifyRecord Design exploration Coupled multiphysics Mesh verification Adjoint optimisation Gradient verification Trust-aware surrogates Full-field ROM Multi-fidelity MDAO Pareto selection High-fidelity reassessment Provenance
Schematic of the platform workflowSchematic
Work with OLTRION

Bring us the design question. Leave with a verified answer and the record behind it.

TensorLynx is built and run by the engineers who use it on client work. You can start small, with one geometry and one question, and grow into a workflow your own team owns.

Feasibility review

Send a geometry, the objective and the constraints. We tell you which TensorLynx route answers it, what it needs from you, and what you will get back.

We run the study

Our engineers run the loop on your problem: physics, sensitivities, optimisation and full-model verification, handed over with every setting on record.

A workflow built for your product

A TensorLynx workflow, surrogate and verification gates set up around your product family, so the next design cycle starts where the last one ended.

Platform access and handover

Your team on TensorLynx, trained on your own cases, with OLTRION engineers behind it for the questions that need a specialist.