Service overview
Stress, vibration, fatigue, nonlinear and composite structural simulation and design optimisation. This service is part of that division and is scoped individually around what you need to learn, decide or publish.
Structural optimisation searches for the dimensions, shape or layout of a structure that best meet an objective, usually minimum mass or cost, while satisfying limits on stress, displacement, frequency or buckling. Combined with finite element analysis, it automates what a designer does by trial and error, and can find configurations that a human would not think to try.
The method is powerful and unforgiving. An optimiser will exploit any weakness in the model, such as a missing load case or an unrealistic support. It will also produce designs that cannot be manufactured unless manufacturing limits are included. The quality of the result therefore depends far more on the formulation than on the algorithm: which variables, which constraints, which load cases and what verification.
If you plan to publish the outcome, see manuscript & publication support, for example computational & simulation manuscripts or original research article writing.
What this service covers
Problems this service can address
- Overly conservative designs that carry unnecessary mass
- Optimised shapes that cannot be manufactured
- Competing constraints such as stiffness and frequency
Methods and analytical approaches
- Size and shape optimisation
- Constraint handling and multi-load-case formulation
- Gradient-based and metaheuristic search
- Verification of optimised designs
Applications
- Lightweight bracket and frame design
- Truss and beam layout
- Research benchmark studies
Relevant engineering disciplines
Scope, inputs and deliverables
Scope of work
- Definition of the physics, geometry and quantities of interest
- Model set-up with verification and, where data allow, validation
- Parametric or sensitivity studies agreed at scoping
- Results and documentation suitable for reports or publication
- Feasibility check on: baseline design and load cases
Typical inputs required from you
- Baseline design and load cases
- Constraints and objectives
- Manufacturing limits
Deliverables
- Optimised design candidates
- Comparison with baseline
- Sensitivity of the optimum to constraints
Highly specialised requests are first checked for feasibility from this information. Please do not send confidential data through the public form; describe it first and agree secure transfer afterwards.
Project workflow and method
- 01Enquiry and requirement assessment
- 02Technical scoping and proposal
- 03Execution
- 04Quality review and delivery, with an agreed round of revisions
Read the full project workflow.
In depth: how the work is done
Formulating objectives, variables and constraints
The objective might be mass, compliance or cost; constraints include allowable stress with safety factors, displacement limits, minimum natural frequency, buckling load and manufacturing limits such as minimum member size. Design variables may be cross-section dimensions, thicknesses, shape parameters or topology. We write the formulation explicitly, discuss whether the objectives conflict and how they will be handled, and check that the feasible region is not empty and does not exclude useful designs.
Multiple load cases and robustness
Real structures see several load cases, and a design optimised for one can fail under another. Multiple load cases are included explicitly, with the governing case possibly changing as the design evolves. We also consider robustness to variations in loads, material properties and imperfections, since an optimum that is only marginally feasible may be unsafe in practice. Safety factors and uncertainty treatment are specified so that the optimiser works against appropriate limits.
Size, shape and layout optimisation
Size optimisation adjusts dimensions such as thickness or cross-section area. Shape optimisation changes the boundary geometry, requiring mesh updating or a parameterisation that keeps mesh quality. Layout optimisation selects member positions and connectivity, for example in trusses. Each class has different search spaces, sensitivities and difficulty. Choosing the lowest-complexity class that can achieve the goal gives more reliable results than starting with the most general.
Algorithms: gradient-based and metaheuristic
Gradient-based methods use sensitivities of responses with respect to variables and converge quickly in problems with many variables and smooth responses, though they may find local optima. Metaheuristics such as genetic algorithms need no gradients, handle discrete variables and can explore multimodal landscapes, but need many evaluations. Hybrid and surrogate-assisted strategies balance cost and robustness. We select the approach according to the number of variables, evaluation cost and the nature of the constraints.
Verification of optimised designs
The optimised design must be verified with an independent, refined analysis: finer mesh, additional load cases, nonlinear or buckling checks that were not in the optimisation loop. Manufacturing feasibility, tolerance sensitivity and joint design are reviewed. Where a prototype or test is possible, it provides the ultimate check. Results are reported with the improvement achieved relative to a baseline and with the conditions under which it was verified.
Quality control and good practice
Quality-control approach
- Verification: mesh, time-step and solver sensitivity are examined before results are reported.
- Validation: results are compared with measurements or reference solutions where these exist, and the absence of such data is stated.
- Boundary conditions and material or fluid properties are recorded with their sources.
- Sensitivity to the least certain inputs is shown or explained.
Common pitfalls this service helps avoid
- Optimising against an incomplete model. Missing load cases or failure modes will be exploited by the optimiser, producing unsafe designs.
- Ignoring manufacturing constraints. Mathematically optimal shapes can be impossible or very costly to make.
- Stopping at a local optimum without checking. Different starting points can give different designs; comparisons reveal whether the result is robust.
- Claiming mass savings without verification. Reported savings must be confirmed with refined models or tests.
What good reporting looks like
A structural optimisation report states the formulation, baseline design, load cases, constraints and allowable values, variable parameterisation, the algorithm and settings, the convergence history, the optimised design and its performance versus the baseline, the verification with refined and additional analyses, manufacturing considerations and limitations. It indicates which assumptions most influenced the result and does not present the optimised design as ready for production without engineering review.
An illustrative scenario
Hypothetical example written for explanation. It is not a client case, a result or a testimonial.
Consider a research group optimising a lightweight bracket with two load cases. Size and shape variables are defined with minimum thickness limits. A gradient-based optimiser reduces mass noticeably, but a verification step with a finer mesh reveals higher stress near a re-entrant corner that the coarse mesh missed. The design is modified with a larger fillet radius and re-verified, and the final report quotes the mass reduction after the corrected analysis, together with a note on the stress at the fillet.
Questions to settle before you begin
- What is the objective, and which constraints are strict?
- Which load cases govern?
- What parameterisation allows useful variation yet remains manufacturable?
- How will I verify the optimised design independently?
- How sensitive is the optimum to my assumptions?
Key terms
- Objective function
- The quantity to be minimised or maximised.
- Design variable
- A parameter that the optimiser can change.
- Constraint
- A limit that a feasible design must satisfy.
- Sensitivity
- The derivative of a response with respect to a design variable.
- Metaheuristic
- A general-purpose search algorithm that does not require gradients.
Working together on Finite Element Analysis (FEA) & Structural Engineering projects
Structural and FEA engagements begin by clarifying what must be predicted, such as stress, stiffness, frequency or life, and which loads and supports are known. We ask for geometry, material data, load cases, connection details and any test measurements. A hand calculation or benchmark is prepared alongside the finite element model to cross-check it. Reports show mesh convergence, state assumptions about supports and materials, and give margins with their uncertainty. The work is research-level analysis and does not replace code-based design checks or certification by licensed professionals.
Frequently asked questions
How does this differ from topology optimisation?
Size and shape optimisation adjust parameters of a given layout; topology optimisation decides where material should exist at all. See the Topology & Design Optimisation service.
Can you optimise topology as well?
Topology optimisation is covered under topology and design optimisation services within the optimisation division.
Will the optimised structure be manufacturable?
Manufacturing constraints can be included if specified. Detailed manufacturing design remains with your engineers.
How do you handle uncertainty in loads?
Through multiple load cases, safety factors or robust optimisation formulations, depending on information available.
Can you use my FEA model?
Yes, if it is documented and verified, or we can review and adapt it.
How is this service scoped and priced?
After your enquiry we review what you need, ask for missing information and send a written scope and quotation. Price depends on complexity, deliverables and timeline. See the project workflow.