Simulation-Driven Product Development

Design Optimization

Improve structural performance without relying on blind trial and error.

Fidelis Aerospace helps aerospace and defense teams identify the design changes that create meaningful engineering value.

By combining structural mechanics, finite element analysis, sensitivity studies, and disciplined trade evaluation, we help improve mass, margins, stiffness, durability, manufacturability, and cost while preserving the requirements and interfaces that make the design work.

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When a Design Works—but Not Well Enough

A design may satisfy its basic function and still carry too much mass, provide inconsistent margins, introduce unnecessary manufacturing complexity, or leave little room for future growth.

The challenge is rarely a lack of possible changes. The challenge is determining which changes improve the design without transferring risk somewhere else.

Reducing thickness may save weight but create a stiffness, buckling, fatigue, or manufacturing problem. Adding material may improve a local margin while increasing load elsewhere. A geometry change intended to relieve one hotspot may create another at an interface or transition.

Design optimization provides a disciplined way to evaluate these interactions before committing to detailed redesign, tooling, testing, or production.

Common Situations

Weight Exceeds the Target

The design meets functional requirements, but its mass threatens vehicle performance, payload, range, cost, or system-level allocation.

Margins Are Uneven

Some regions are heavily overbuilt while a small number of local details govern the design.

The Load Path Is Inefficient

Geometry, interfaces, or stiffness distribution cause unnecessary bending, secondary load, deformation, or stress concentration.

Requirements Compete

Strength, stiffness, fatigue life, thermal behavior, cost, packaging, and manufacturing constraints point toward different design choices.

Redesign Is Becoming Reactive

Repeated local fixes are being made without a clear understanding of their system-level consequences.

Several Concepts Appear Viable

The team needs a defensible comparison of geometry, material, configuration, or manufacturing alternatives.

A focused optimization effort can help determine:

Which design variables have the greatest influence on performance?
Where is material providing useful structural capability—and where is it not?
Which locations or failure modes actually govern the design?
Can mass be reduced without creating unacceptable strength, stiffness, fatigue, fracture, or stability risk?
Would a change in geometry, material, thickness, load path, joint configuration, or support condition provide the greatest benefit?
How sensitive is the design to uncertain loads, material properties, dimensions, or boundary conditions?
Are local improvements transferring stress, deformation, or load into another part of the structure?
Which design alternative provides the best overall balance of performance, complexity, cost, and risk?
What additional analysis, testing, or manufacturing input is needed before selecting a final configuration?
When has the design been improved enough to justify moving forward?

The objective is not to generate the largest possible number of alternatives. It is to identify the changes most likely to improve the engineering decision.

Turn Competing Tradeoffs into a Clearer Design Direction

Design optimization should produce more than a lighter model or a new geometry. It should establish why the recommended design is better and what limitations remain.

Identify What Governs

Determine the loads, failure modes, interfaces, requirements, and constraints controlling the current design.

Find the High-Leverage Variables

Separate changes that materially influence performance from those that add complexity without meaningful benefit.

Compare Alternatives Consistently

Evaluate candidate designs against the same requirements, assumptions, load cases, and decision criteria.

Understand the Tradeoffs

Make the consequences of weight, margin, stiffness, durability, cost, manufacturing, and integration decisions visible.

Reduce Redesign Risk

Challenge proposed changes before they become embedded in drawings, tooling, qualification hardware, or production plans.

Establish the Next Design Baseline

Provide a documented basis for selecting, refining, verifying, or rejecting a candidate configuration.

Typical outcomes may include:

A lighter design with acceptable structural margins.
Better-balanced margins across components or failure modes.
Reduced stress concentration or secondary bending.
Improved stiffness or load-path behavior.
Greater fatigue or durability capability.
Simplified fabrication, assembly, or inspection access.
A ranked set of design alternatives.
A clear recommendation for detailed design and verification.

The scope is tailored to the decision being made, the maturity of the design, and the evidence available.

Baseline Design Assessment

Establish how the current configuration carries load and identify the features, assumptions, and failure modes limiting performance.

Typical activities may include:

Review of geometry, materials, interfaces, and requirements.
Examination of existing hand calculations or finite element models.
Identification of governing loads and load paths.
Review of margins, deformation, stability, fatigue, or fracture concerns.
Evaluation of modeling assumptions and evidence quality.
Identification of overbuilt and underperforming regions.

Parametric and Sensitivity Studies

Determine how changes in selected design variables influence the engineering response.

Variables may include:

Thicknesses and section dimensions.
Fillet radii and transition geometry.
Fastener quantity, size, spacing, or pattern.
Stiffener location and section properties.
Support or attachment stiffness.
Material selection.
Load introduction geometry.
Cutout, flange, rib, web, or bracket configuration.
Manufacturing tolerances or dimensional variation.

Sensitivity studies help distinguish high-value variables from changes that provide little practical benefit.

Structural Efficiency and Margin Balancing

Improve the distribution of structural capability rather than adding or removing material indiscriminately.

This may include:

Reducing unnecessary material in low-demand regions.
Increasing capability at governing locations.
Improving section efficiency.
Redirecting load into more effective structural paths.
Reducing secondary bending or eccentricity.
Balancing competing failure modes.
Avoiding excessive local margin at the expense of system mass.

Geometry and Load-Path Refinement

Modify geometry to improve how load enters, travels through, and exits the structure.

Potential areas of study include:

Local transitions and discontinuities.
Attachment and interface geometry.
Brackets, fittings, lugs, clevises, ribs, webs, and stiffeners.
Joint eccentricity and bypass loading.
Panel reinforcement and cutout details.
Load introduction and restraint conditions.
Local stiffness compatibility between connected components.

Material and Configuration Trades

Compare alternative materials or structural arrangements against defined performance and program constraints.

Trade considerations may include:

Strength and stiffness.
Density and mass.
Fatigue and fracture behavior.
Temperature or environmental requirements.
Corrosion or compatibility concerns.
Availability and procurement risk.
Manufacturing process.
Inspection and repair considerations.
Cost and schedule implications.

Durability-Aware Optimization

Evaluate whether a proposed static-strength improvement creates an unacceptable repeated-loading or damage-growth consequence.

Depending on the design and available data, optimization may consider:

Fatigue-critical hotspots.
Stress concentration reduction.
Load-spectrum sensitivity.
Joint and fastener load redistribution.
Surface or geometry effects.
Crack-sensitive details.
Inspection access and damage tolerance.
Tradeoffs between static margin and service life.

Manufacturability and Assembly Trade Support

Incorporate relevant production and integration constraints into the engineering trade.

This may include:

Part count and assembly complexity.
Machining or fabrication constraints.
Fastener and tool access.
Tolerance sensitivity.
Minimum material or process dimensions.
Standard material forms and thicknesses.
Interface stability.
Inspection accessibility.
Repairability and maintainability.

Manufacturing decisions remain dependent on the client’s process knowledge, supplier capabilities, quality system, and production requirements.

Candidate Design Verification

Evaluate the selected design against the requirements and failure modes included in the agreed scope.

Verification may include:

Updated hand calculations.
Revised finite element analysis.
Comparison with the original baseline.
Margin and sensitivity review.
Assessment of transferred loads or new hotspots.
Fatigue or durability screening.
Documentation of assumptions and limitations.
Identification of remaining evidence needs.

Design optimization is most effective when the objective, constraints, and governing technical basis are clearly defined.

Optimization Is Not Simply Automated Geometry Generation

Topology optimization, generative design, or automated parameter search may be useful for selected problems, but they are not substitutes for understanding load paths, interfaces, failure modes, manufacturing constraints, and uncertainty.

The method should follow the engineering decision—not the availability of a software feature.

Optimization Does Not Guarantee a Predetermined Result

A specific mass reduction, cost reduction, or performance increase cannot be established before the baseline design and governing constraints are understood.

The technically correct outcome may be to retain the current design, modify the requirement, collect additional evidence, or focus on a different subsystem.

Optimization Does Not Automatically Constitute Final Substantiation

Concept screening and comparative studies may identify a preferred direction without completing every analysis required for release, qualification, certification, or continued operation.

Final substantiation can be included when clearly defined in the engagement scope.

Related Service Boundaries

Simulation-Driven Design

Best suited to integrating analysis throughout concept development and early design iteration.

Aerospace Structures Design

Best suited to creating or substantially revising structural architecture, load paths, interfaces, and layouts.

Mechanical Design

Best suited to detailed CAD development, assemblies, drawings, packaging, and production definition.

Structural Analysis & Finite Element Analysis

Best suited to determining structural response, governing failure modes, and margins for a defined configuration.

Fatigue Life & Durability Assessment

Best suited to evaluating repeated-loading life and durability implications in greater depth.

Fracture Mechanics & Damage Tolerance

Best suited to flaw significance, crack growth, residual strength, and inspection-related decisions.

A single engagement may combine several of these services when the design decision requires an integrated approach.

Fidelis Aerospace approaches optimization as an engineering decision process—not as an exercise in producing the lowest numerical objective function.

Frame the Decision

Define what the design is expected to improve and what must remain protected.

This includes:

The decision to be made.
Performance objectives.
Requirements and constraints.
Critical interfaces.
Permitted design variables.
Relevant load cases.
Manufacturing limitations.
Schedule and maturity expectations.
Required level of evidence.

Establish the Technical Basis

Create a trustworthy baseline before comparing alternatives.

This may involve:

Confirming loads and boundary conditions.
Reviewing load paths and structural behavior.
Identifying governing failure modes.
Verifying existing calculations or models.
Establishing comparison metrics.
Documenting assumptions, uncertainties, and data gaps.

An optimization result is only as credible as the technical basis used to evaluate it.

Analyze, Verify, and Challenge

Evaluate sensitivities and candidate changes using methods appropriate to the problem.

Activities may include:

Classical structural calculations.
Finite element analysis.
Parametric studies.
Material and geometry trades.
Margin balancing.
Fatigue or fracture screening.
Manufacturability review.
Independent checks and model verification.
Examination of unintended consequences.

The objective is to understand both why an alternative improves performance and where it may introduce new risk.

Convert Findings into Action

Rank the alternatives, identify the preferred direction, and define what should happen next.

The recommendation may support:

Selection of a revised configuration.
Further detailed design.
Additional analysis or testing.
Manufacturing consultation.
Requirement refinement.
Risk retirement planning.
PDR or CDR preparation.
Deferral of a change that does not provide sufficient value.

Engagements can be structured around the maturity of the design and the size of the decision.

Design Optimization Screening

A bounded initial assessment used to determine whether a meaningful optimization opportunity exists.

Appropriate when:

The design appears heavy or inefficient.
A small number of locations govern.
The team is unsure which variables matter.
Several alternatives are under consideration.
The required level of analysis is not yet clear.

Typical output:

Baseline observations.
Likely governing constraints.
High-leverage design variables.
Major risks and data gaps.
Recommended optimization scope.
Initial next-step plan.

Focused Design Optimization Study

A defined study addressing one component, assembly, objective, or family of design variables.

Examples include:

Reducing bracket or fitting mass.
Improving a local strength margin.
Reducing deformation.
Refining a joint or attachment.
Comparing candidate materials.
Balancing mass and fatigue performance.
Evaluating manufacturing alternatives.

Typical output:

Verified baseline.
Sensitivity results.
Candidate alternatives.
Comparative trade matrix.
Ranked recommendations.
Verification findings.
Documented limitations and next actions.

Integrated Optimization Support

Iterative engineering support through multiple design cycles.

This pathway may include:

Design-team participation.
CAD and analysis iteration.
Progressive trade refinement.
Review preparation.
Test-informed updates.
Configuration comparisons.
Final design verification.
Technical decision support.

This approach is appropriate when optimization is part of a larger product-development effort rather than a single isolated study.

The exact inputs depend on the objective and design maturity. Useful information may include:

Design Definition

CAD models.
Drawings and interface-control information.
Material and process specifications.
Assembly definition.
Configuration history.
Packaging and envelope constraints.

Requirements and Constraints

Strength and stiffness requirements.
Mass targets or allocations.
Life and durability objectives.
Thermal or environmental requirements.
Manufacturing limitations.
Inspection or maintenance constraints.
Cost or schedule considerations.
PDR, CDR, qualification, or release criteria.

Loads and Operating Conditions

Applied loads and load combinations.
Inertial and pressure loads.
Thermal conditions.
Dynamic or vibration environments.
Usage spectra.
Load factors and uncertainty.
Boundary and interface conditions.

Existing Evidence

Hand calculations.
Finite element models and reports.
Margin summaries.
Test data.
Failure or anomaly information.
Manufacturing feedback.
Prior trade studies.
Known technical risks.

Incomplete inputs do not always prevent an initial study, but their effect on confidence and conclusions will be made explicit.

Deliverables are selected to support the client’s decision rather than to produce unnecessary documentation.

A design optimization engagement may provide:

Baseline structural assessment.
Optimization objective and constraint definition.
Governing requirement and failure-mode summary.
Sensitivity or parametric study results.
Load-path and structural-behavior findings.
Candidate geometry or configuration concepts.
Material or manufacturing trade evaluation.
Mass, margin, stiffness, or durability comparisons.
Revised CAD concepts when included in scope.
Updated calculations or finite element models.
Design trade matrix.
Ranked recommendations.
Identification of transferred or residual risks.
Assumptions, limitations, and uncertainty statement.
Verification recommendations.
Test or evidence-development recommendations.
Technical memorandum, calculation package, or presentation.
Review support for the recommended configuration.

The final deliverable should make clear:

What governed the original design.
What alternatives were evaluated.
Why the recommended alternative performed better.
What tradeoffs remain.
What evidence supports the recommendation.
What should happen next.

Senior Engineering Judgment at the Design–Analysis Interface

Effective optimization requires more than CAD proficiency or the ability to run an analysis model. It requires an understanding of how geometry, mechanics, failure modes, manufacturing constraints, and program decisions interact.

Fidelis Aerospace brings more than 20 years of aerospace product-development and structural-analysis experience to these decisions.

Senior-Led Delivery

Clients work directly with an experienced aerospace engineer who can connect detailed analysis to the larger product and program decision.

Physics-First Reasoning

Changes are evaluated through mechanics, load paths, assumptions, failure modes, sensitivity, and verification—not only through software-generated results.

Integrated Design and Analysis

Design, structural analysis, fatigue, fracture, manufacturability, and technical risk are treated as connected considerations.

Practical Product-Development Judgment

Recommendations account for interfaces, configuration maturity, review expectations, testing, manufacturing, and the realities of moving hardware forward.

Decision-Centered Outcomes

The objective is not simply to produce another model. It is to establish a clearer, defensible basis for selecting and advancing the design.

What is design optimization?

Design optimization is the disciplined improvement of a design against defined objectives and constraints.

The objective might be lower mass, better margins, increased stiffness, longer life, reduced complexity, improved manufacturability, or a balanced combination of several factors.

It includes understanding the baseline, identifying influential variables, evaluating alternatives, and verifying that the recommended changes do not create unacceptable consequences elsewhere.

Is design optimization the same as topology optimization?

No.

Topology optimization is one computational method that can help identify efficient material distribution within a defined design space. It can be useful for selected problems, particularly during early development.

Design optimization is broader. It may include analytical calculations, finite element analysis, sensitivity studies, material trades, configuration changes, joint refinement, margin balancing, manufacturability considerations, fatigue, and engineering judgment.

Topology optimization is used only when it is appropriate to the decision and the resulting geometry can be interpreted, manufactured, integrated, and substantiated.

Can you reduce weight without reducing structural capability?

Often, but not automatically.

Weight may be reduced by improving load paths, refining local geometry, balancing margins, changing section properties, modifying joints, or selecting a different material or configuration.

The achievable reduction depends on the baseline design, requirements, manufacturing limits, interfaces, load uncertainty, and governing failure modes. Proposed changes must be checked for strength, stiffness, stability, fatigue, fracture, and other relevant consequences.

Can optimization include fatigue and durability?

Yes.

A design that improves static margin may still create a fatigue-sensitive detail, and a weight-reduction change may increase cyclic stress or load transfer.

Fatigue, durability, fracture, or damage-tolerance considerations can be included when they are relevant to the design objective and sufficient input data are available.

Can Fidelis work with an existing CAD model or finite element model?

Yes.

Existing models, calculations, and reports can provide a useful starting point. Their assumptions, idealizations, boundary conditions, mesh strategy, load application, and verification status should be reviewed before they are relied upon as the optimization baseline.

Model compatibility, access, and the required level of revision are confirmed during scoping.

At what stage should design optimization begin?

Optimization is valuable throughout development, but the available design freedom changes with maturity.

Early in development, larger changes to architecture, material, interfaces, and load paths may still be practical. Later in development, optimization usually becomes more targeted and must account for released interfaces, tooling, qualification status, supplier commitments, and change cost.

The earlier a governing structural issue is understood, the more options the team usually retains.

How is this different from Simulation-Driven Design?

Simulation-Driven Design integrates analysis throughout the creation and development of a design.

Design Optimization focuses more specifically on improving a baseline or candidate design against defined objectives and constraints.

The services frequently overlap. A simulation-driven development program may contain several optimization cycles as the design matures.

Can you guarantee a specific weight or cost reduction?

No predetermined improvement should be promised before the baseline, requirements, and constraints are understood.

An optimization study may reveal substantial improvement potential, modest opportunity, or a technically justified reason to retain the current design. Fidelis will communicate what the evidence supports rather than forcing a preferred commercial outcome.

Does the service include final CAD and production drawings?

It can, when specifically included in the scope.

Some engagements end with design recommendations and conceptual geometry. Others may include revised CAD, detailed definition, drawings, or further structural substantiation through related design and analysis services.

The required level of design definition is established before work begins.

Find the changes that create real engineering value.

Whether the objective is lower mass, improved margins, greater durability, reduced complexity, or a more manufacturable configuration, the first step is to understand what governs the current design.

Fidelis Aerospace can help frame the optimization problem, evaluate the available evidence, identify the highest-leverage variables, and establish a defensible path toward a better design.

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