Independent Fatigue & Fracture Review
Independent technical review of fatigue and fracture mechanics for spaceflight hardware
Fidelis Aerospace independently reviews fatigue analyses, fracture mechanics assessments, crack-growth predictions, supporting stress solutions, material data, test evidence, assumptions, and engineering conclusions before a client relies on them for an important hardware decision.
The purpose is not to add another layer of process. It is to examine the technical basis from an independent senior perspective, challenge important assumptions, identify material gaps, confirm sound work, and improve confidence in the decision.
When to engage Fidelis for an independent technical review
- A fatigue or fracture assessment is approaching release, customer submittal, design review, test readiness, qualification, flight, reuse, or another consequential decision.
- A predicted fatigue life or crack-growth result is difficult to explain, unusually sensitive, or inconsistent with test evidence or expected mechanics.
- The internal team does not have a senior fatigue or fracture specialist available to independently review the work.
- Different analysts, suppliers, or organizations have reached different conclusions about fatigue life, crack growth, flaw criticality, or residual strength.
- A crack, manufacturing defect, nonconformance, test discrepancy, or unexpected failure has increased the consequence of an incorrect assumption.
- Supplier-generated or partner-generated fatigue or fracture analysis must be reviewed before it becomes part of the program technical basis.
- A program needs an independent perspective on whether the available fatigue or fracture evidence adequately supports the intended hardware decision.
What an independent fatigue or fracture review can examine
Hardware, requirements, and loading
Check that the analyzed configuration, life requirement, mission profile, loading spectrum, environments, material condition, and acceptance criteria correspond to the actual hardware and engineering decision being supported.
Method applicability and assumptions
Examine whether the selected fatigue, fracture mechanics, crack-growth, cumulative-damage, stress, or strain methods are appropriate for the governing behavior, available data, and intended use of the result.
Identify assumptions or simplifications that materially influence the conclusion.
Stress and strain basis
Review the local stress or strain inputs used by the fatigue or fracture assessment.
This may include examination of classical calculations, finite element results, load introduction, local structural behavior, boundary conditions, stress extraction, notch treatment, residual stress, thermal response, and other supporting mechanics where they affect structural life or crack behavior.
Fatigue basis
Review loading spectra, cycle counting, stress-life or strain-life methods, mean-stress corrections, cumulative-damage assumptions, material fatigue data, modifying factors, local detail treatment, reliability or scatter considerations, and predicted life.
Fracture mechanics basis
Review crack scenarios, initial-flaw assumptions, crack geometry, stress-intensity or other fracture parameters, fracture toughness, fatigue crack-growth data, load interaction assumptions, critical flaw size, residual strength, and crack-growth life.
Material and manufacturing basis
Examine whether fatigue, fracture toughness, and crack-growth data appropriately represent the material condition, manufacturing process, heat treatment, temperature, environment, surface condition, additive-manufacturing state, or other factors relevant to the hardware.
Test evidence and correlation
Compare analytical predictions with available fatigue, fracture, component, qualification, or development-test evidence.
Review whether observed crack locations, lives, failure modes, strains, loads, or other measurements support the analytical assumptions and conclusions.
Sensitivity and uncertainty
Determine which assumptions, inputs, material properties, loads, flaw definitions, or modeling choices most strongly influence the result and whether significant uncertainty has been recognized appropriately.
Technical conclusions and traceability
Assess whether the analysis clearly connects the hardware configuration, inputs, assumptions, methods, evidence, limitations, results, and conclusions.
The review asks whether the stated engineering conclusion is supported by the technical evidence—not simply whether calculations were completed.
Review depth is scoped to the decision
Independent review does not automatically mean re-performing the entire analysis.
A review may focus on:
- A fatigue-life calculation.
- A loading spectrum or cycle definition.
- A critical fatigue location.
- A fracture mechanics assessment.
- A fatigue crack-growth prediction.
- An assumed initial flaw.
- A critical flaw or residual-strength calculation.
- A supporting stress or strain solution.
- Material fatigue or fracture data.
- A test-correlation discrepancy.
- A manufacturing-defect assessment.
- An integrated fatigue and fracture technical basis.
Independent calculations or models can be developed when they materially improve confidence in the governing conclusion.
Independent checks where they matter most
A complete parallel analysis is not always the most effective way to review technical work.
Fidelis can perform focused independent checks of critical portions of the analysis, such as:
- Recalculating a governing fatigue location.
- Independently estimating fatigue damage or life.
- Checking a stress-intensity solution.
- Repeating a crack-growth calculation using independent assumptions or software.
- Evaluating sensitivity to initial flaw size.
- Checking critical flaw size or residual strength.
- Comparing alternative material data.
- Reviewing the effect of mission-spectrum assumptions.
- Comparing finite element stress results with simplified analytical calculations.
- Assessing whether test behavior is consistent with the analytical model.
These checks are selected based on the technical risk and the decision the review must support.
Information commonly needed
- Hardware configuration and the engineering decision being supported.
- Fatigue, fracture, crack-growth, structural-life, or fracture-control requirements.
- Calculations, analysis reports, models, drawings, loads, spectra, and stress or strain results.
- Material fatigue, fracture toughness, and crack-growth data.
- Manufacturing and defect information where relevant.
- Known concerns, disputed assumptions, open comments, or prior review findings.
- Applicable fatigue, fracture, or component-test data.
- Observed cracks, failures, anomalies, or nonconformance records where applicable.
- The requested review depth and expected form of the findings.
Potential outputs
Depending on scope, outputs may include:
- Independent technical-review memorandum.
- Comment or findings matrix.
- Marked-up fatigue or fracture analysis.
- Critical-assumption review.
- Independent spot calculations.
- Crack-growth verification calculations.
- Sensitivity or uncertainty assessment.
- Material-data review.
- Test-correlation findings.
- Identification of technical gaps.
- Recommended corrections or additional analysis.
- Recommended test or data needs.
- Meeting or design-review support.
- Written independent technical opinion.
The scope and deliverables are defined around the actual hardware decision.
Independent review versus performing the analysis
Fidelis can either perform a fatigue or fracture analysis directly or independently review work prepared by another organization.
An independent review is appropriate when the client already has an analytical basis but wants another experienced technical perspective before relying on it.
The review is not intended to replace the original analyst or duplicate every calculation. Its purpose is to determine whether the assumptions, methods, evidence, and conclusions are technically defensible for the decision being made.
When the review identifies a specific technical gap, Fidelis can separately scope additional fatigue, fracture mechanics, crack-growth, or supporting analysis if needed.
Need an independent check before relying on the fatigue or fracture analysis?
Share a non-sensitive description of the hardware, the analysis to be reviewed, the technical concern, and the decision it must support.
Fidelis can help determine the appropriate review depth and which portions of the technical basis deserve the most independent attention.
Frequently Asked Questions
What is an independent technical review?
An independent technical review is an objective examination of engineering work by a qualified reviewer who was not responsible for developing the original technical basis.
For Fidelis, the review focuses on fatigue, fracture mechanics, crack growth, structural life, and the supporting engineering evidence required to evaluate those conclusions.
Does Fidelis have to repeat the entire analysis?
No.
Review depth depends on the technical risk, available evidence, and engineering decision.
A review may focus on assumptions, methods, material data, loading, selected calculations, critical locations, crack-growth predictions, sensitivities, or conclusions. Independent calculations are added where they provide useful evidence.
Can Fidelis review supporting FEA?
Yes, when the finite element analysis provides stress, strain, temperature, load-path, or other inputs used by the fatigue or fracture assessment.
The FEA is reviewed in the context of the fatigue or fracture decision rather than as a standalone general-purpose model-review service.
Can Fidelis review another supplier's fatigue or fracture analysis?
Yes.
Independent review can be applied to internally generated, supplier-generated, partner-generated, or consultant-generated fatigue and fracture analyses.
The objective is to evaluate the technical basis objectively regardless of who produced the original work.
Can Fidelis independently verify a crack-growth calculation?
Yes.
Depending on scope, Fidelis can review the existing crack-growth model, input spectrum, crack geometry, material data, assumptions, and results and can perform independent verification calculations where appropriate.
Can Fidelis review fatigue or fracture test correlation?
Yes.
A review can compare analytical predictions with observed crack locations, fatigue life, failure behavior, strain measurements, loads, or other test evidence and identify possible reasons for disagreement.
Is an independent technical review the same as certification or formal approval?
No.
Fidelis can provide an independent engineering opinion and identify technical findings, but the review does not create certification authority, design authority, delegated approval authority, or another formal compliance role that has not been assigned to Fidelis.
Will Fidelis issue findings if the analysis is technically sound?
Yes.
The objective is not to manufacture criticism. An independent review may confirm that the approach is appropriate, identify strengths in the technical basis, document limitations, identify specific corrections, or recommend additional evidence in proportion to what the review supports.