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.
Stress and strain analysis answers the practical question of whether a member or assembly will carry its loads without exceeding strength or deflection limits. It is the foundation of structural design and of failure investigation. Many cases can be handled analytically with beam, plate and shell theory, which provide transparent estimates; complex geometry and loading call for finite element models, which should be compared with those analytical estimates.
A stress value has meaning only against a criterion: yield, ultimate strength, buckling or fatigue limit, each of which has its own appropriate measure of stress. Linking the computed state of stress to the correct failure criterion, and quantifying margins and uncertainty, is as important as computing the stress.
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
- Locating critical sections and stress concentrations
- Comparing computed stresses with allowable values
- Load paths that are unclear in complex assemblies
Methods and analytical approaches
- Analytical beam, plate and shell estimates
- Linear static FEA
- Stress-concentration and local-detail analysis
- Failure-criterion evaluation
Applications
- Bracket and frame assessment
- Pressure-component evaluation
- Research component stress mapping
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: geometry, materials and load cases
Typical inputs required from you
- Geometry, materials and load cases
- Applicable acceptance criteria
- Strain-gauge or test data, if any
Deliverables
- Stress and strain maps
- Margin summary against agreed criteria
- Notes on conservatism and limitations
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
Analytical estimates first
Beam theory gives bending and shear stresses and deflections for slender members; plate and shell theory handle flat and curved panels; thin-walled pressure vessel formulas give hoop and axial stress. These estimates are quick, show the dependence on dimensions and loads and provide a benchmark for numerical models. Their limitations, such as slenderness assumptions and neglect of local effects, are stated so that users know when to move to a finite element model.
Finite element stress analysis
Linear static FEA computes the stress field in complex shapes. Mesh quality and element type determine accuracy, particularly in regions of high gradient. Results are examined as von Mises or principal stresses depending on the material, and nominal stresses away from discontinuities are compared with analytical values. Loads and constraints are checked for equilibrium and realism, since they are the main source of error in practice.
Stress concentrations and local details
Holes, fillets, notches and welds raise local stress above the nominal value by a stress concentration factor. Handbook factors give estimates for standard geometries; FEA models of the local detail with a refined mesh provide values for others. Submodelling uses a coarse global model to provide boundary conditions to a refined local model. For brittle materials and fatigue, local stress matters directly; for ductile materials under static load, local yielding often redistributes stress.
Failure criteria and margins
The computed stress state is compared with an appropriate criterion: von Mises or Tresca for yielding of ductile metals, maximum principal stress for brittle materials, buckling analyses for slender compression members and specialised criteria for composites. Safety factors or margins of safety express how close the structure is to its limit. We state which criterion is used and why, the allowable values and their source, and the effect of uncertainty in loads and properties on the margin.
Serviceability: deflection and stiffness
Stiffness may govern design even when strength is adequate: excessive deflection can impair function, cause misalignment or lead to vibration problems. We report deflections at critical points and compare them with limits, and we examine the sensitivity of stiffness to the boundary conditions and joint flexibility, which are often more important than material stiffness.
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
- Quoting peak stress at a singularity. Numerically high stress at a sharp corner or point load may not be physically meaningful.
- Using the wrong failure criterion. Applying a ductile-material criterion to a brittle material, or the reverse, misstates the margin.
- Ignoring residual and thermal stress. Manufacturing and thermal effects can add significant stresses to those from mechanical loading.
- Neglecting joint flexibility. Assuming rigid connections overestimates stiffness and misplaces stresses.
What good reporting looks like
A stress report defines the structure, loads, supports and materials, describes the analytical and numerical methods, presents the stress and deflection results with locations and units, states the failure criteria and allowables, gives margins and their sensitivity to uncertain inputs, and records the checks against hand calculations. It distinguishes nominal and local stresses, notes unresolved uncertainties and does not substitute for code-based design verification by qualified professionals.
An illustrative scenario
Hypothetical example written for explanation. It is not a client case, a result or a testimonial.
Suppose a research group needs the stress in a loaded frame joint. A beam-theory estimate gives nominal stress in the members, and a finite element model of the joint shows a peak at a weld toe, which is a modelling singularity. A submodel with a realistic weld radius gives a finite local stress, which is compared with the material's allowable. The report states the nominal margin, the local margin and the uncertainty in the weld geometry, recommending a fatigue assessment if the loading is cyclic.
Questions to settle before you begin
- Which failure mode governs: yielding, fracture, buckling or fatigue?
- Are my loads known or estimated?
- Which local details need refined modelling?
- What allowable values apply and where do they come from?
- What deflection limits matter for function?
Key terms
- Von Mises stress
- An equivalent stress used to predict yielding of ductile materials.
- Principal stress
- The normal stress on planes where shear stress vanishes.
- Stress concentration factor
- The ratio of local peak stress to nominal stress.
- Margin of safety
- A measure of how much capacity remains beyond the applied load.
- Submodelling
- Using results from a coarse model as boundary conditions for a detailed local model.
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
Do you certify structural adequacy?
No. We provide analysis in support of research and engineering decisions. Certification and sign-off are the responsibility of licensed engineers or authorised bodies.
Can you evaluate a bracket or frame I describe?
Yes, given geometry, loads, supports and material data. Missing details are listed and assumptions agreed.
Do you include buckling?
Linear and nonlinear buckling analyses can be included for slender members and thin shells when in scope.
Can you assess pressure components?
Research-level stress evaluation is possible, but code-compliant design and certification must be done by licensed professionals.
How do you treat welds?
Welds can be represented by appropriate idealisations or local models, and the limits of that idealisation are stated.
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.