Langford Analytic · Knowledge Base
How-To Guides
Practical engineering methods, from defining the problem to checking the answer. Step-by-step workflows for common engineering tasks — combining analytical methods, finite-element analysis and engineering judgement with the verification checks needed to produce a defensible result.
FEA & Model Building
How to Plan an FEA Before Building the ModelThe decisions made before opening preprocessing software have the greatest influence on whether the analysis answers the right engineering question. This guide provides a structured planning workflow.How to Choose the Right Element TypeElement selection determines whether the model captures the relevant physics. This guide explains when to use beams, shells, solids and continuum shells, and how to avoid the common pitfalls of each.How to Perform a Mesh Convergence StudyA mesh convergence study demonstrates that the finite element mesh is fine enough to produce a stable solution. This guide provides the systematic procedure and explains what convergence does and does not prove.How to Apply Boundary Conditions Without Over-Constraining a ModelOver-constraint is one of the most common and least detected FEA errors. This guide explains how to represent physical supports faithfully and check that constraints are not artificially stiffening the model.How to Introduce Loads into an FE ModelThe way loads are applied to an FE model affects the local stress distribution near the application point. This guide explains how to introduce loads realistically and avoid artificial stress concentrations.How to Set Up and Verify Contact in an FE ModelContact modelling introduces nonlinear behaviour that can be physically realistic but numerically challenging. This guide explains how to define contact, choose formulation parameters and verify that the contact solution is correct.How to Decide Whether an Analysis Needs to Be NonlinearRunning a nonlinear analysis when a linear one would suffice wastes time. Running a linear analysis when nonlinearity is significant produces wrong answers. This guide explains how to decide.How to Model Bolts and Fasteners in FEABolts can be modelled at many fidelity levels, from simple beam representations to full 3D solids with preload. This guide explains the options and when to use each.How to Model Welded Connections in FEAWelded connections can be modelled as tied interfaces, solid weld beads or shell-solid transitions. This guide explains the options and how to choose based on the engineering objective.How to Use SubmodellingSubmodelling allows a detailed local model to inherit boundary conditions from a coarser global model. This guide explains when and how to use submodelling correctly.How to Check an FE Model Before Reviewing Stress ResultsBefore looking at stress contours, verify that the model is physically and numerically sound. This guide provides a pre-results checklist that catches the most common modelling errors.How to Verify an FE ModelVerification confirms that the numerical model was built correctly. This guide provides the complete verification workflow, from unit consistency through mesh convergence to hand calculation correlation.
Loads & Boundary Conditions
How to Build a Defensible Load CaseA load case is more than a set of forces. It is a traceable engineering record connecting the operating environment to the analysis. This guide explains how to construct one properly.How to Draw and Use a Free-Body DiagramThe free-body diagram is the most important tool in structural analysis. This guide explains how to construct one correctly and use it to understand the load path before building any model.How to Identify the Structural Load PathBefore analysing stresses, the engineer must understand how loads travel from their point of application to the supports. This guide provides a systematic approach to load path identification.How to Apply Distributed Loads Correctly in FEADistributed loads — pressure, line load, body force — must be applied with an understanding of how the software distributes them across elements. This guide explains the correct approach.How to Apply Bearing and Pressure LoadsBearing loads on holes and contact surfaces require careful representation to avoid artificial stress concentrations. This guide explains the correct approach for bearing and pressure load application.How to Transfer CFD Pressure Loads into an FE ModelMapping CFD pressure onto an FE mesh requires careful attention to interpolation, mesh mismatch and total resultant. This guide explains the correct workflow.How to Define Inertial and Acceleration LoadsInertial loads — gravity, acceleration, rotation — are body forces that act on every element with mass. This guide explains how to define them correctly and verify the resulting force distribution.How to Build Load CombinationsReal structures experience multiple loads simultaneously. This guide explains how to combine loads correctly, when to apply combination factors, and how to identify the critical combination.How to Identify the Critical Load CaseWith dozens of load cases, the critical case is rarely obvious. This guide explains how to systematically identify the governing load case for each structural location and failure mode.How to Check Applied Loads Using Reactions and EquilibriumThe reaction force check is the simplest and most powerful verification in FEA. This guide explains how to perform it and what to do when it fails.
Static Strength & Stability
How to Perform a Static Strength AssessmentA static strength assessment demonstrates that a structure can sustain the ultimate load without rupture. This guide provides the complete workflow from load identification to margin reporting.How to Calculate Margin of SafetyThe margin of safety is the fundamental measure of structural reserve. This guide explains the correct calculation for single and combined stress states.How to Check Combined StressReal structures rarely experience a single stress component. This guide explains how to assess combined stress states using interaction equations and failure criteria.How to Check Bearing StressBearing stress at fastener holes and lug interfaces is a critical failure mode in bolted and pinned joints. This guide provides the complete bearing stress check workflow.How to Check a LugLugs are critical structural components subject to bearing, shear tear-out and net-section tension. This guide provides the complete lug assessment workflow.How to Check a Fastener GroupMulti-fastener joints require load distribution analysis before individual fastener checks. This guide explains how to determine fastener loads and check the group.How to Assess Column BucklingColumn buckling is a stability failure mode where a slender member under compression suddenly deflects laterally. This guide explains the assessment workflow.How to Interpret an Eigenvalue Buckling AnalysisLinear eigenvalue buckling provides a theoretical buckling load factor, but the result must be interpreted with care. This guide explains what it does and does not tell you.How to Decide Whether Nonlinear Buckling Analysis Is RequiredLinear eigenvalue buckling is fast but optimistic. This guide explains when nonlinear buckling analysis is needed and what it adds.How to Separate Real Stress Concentrations from FE SingularitiesNot every high stress in an FEA result is real. This guide explains how to distinguish a genuine stress concentration from a numerical singularity.
Joints & Interfaces
How to Calculate Bolt Shear CapacityA step-by-step guide to calculating the shear capacity of a bolted joint, from identifying bolt grade to computing the final margin of safety.How to Define Bolt PreloadBolt preload determines joint integrity under external load. This guide explains how to specify, apply and verify preload in both hand calculations and FEA.How to Check a Bolted JointA complete bolted joint assessment checks bolt strength, bearing, joint separation and clamp-up loss. This guide provides the systematic workflow.How to Determine Whether a Bolted Joint Will SeparateJoint separation changes the load path and can lead to rapid bolt failure. This guide explains how to calculate the separation load and check the separation margin.How to Extract Bolt Loads from an FE ModelExtracting bolt forces from FEA requires understanding what the model represents and where to query the results. This guide explains the correct extraction methods for different bolt modelling approaches.How to Assess a Welded JointWelded joint assessment involves checking throat strength, weld toe stress concentration and weld fatigue. This guide provides the assessment workflow for static and fatigue conditions.
Fatigue & Damage
How to Perform an S-N Fatigue AssessmentThe S-N approach is the standard method for high-cycle fatigue assessment. This guide explains the complete workflow from stress range determination to life prediction.How to Use a Goodman DiagramThe Goodman diagram corrects fatigue strength for mean stress. This guide explains how to construct and use it correctly.How to Apply Miner's RuleMiner's rule is the standard method for cumulative fatigue damage under variable-amplitude loading. This guide explains how to apply it correctly and when to be cautious.How to Assess Weld FatigueWeld fatigue differs from parent material fatigue — the weld toe is a stress concentration that cannot be removed. This guide explains the IIW assessment workflow.How to Interpret Fatigue Life from FEAFEA provides the stress field, but fatigue life prediction requires correct stress extraction, modification and S-N curve entry. This guide explains the workflow.How to Assess a Stress Concentration for FatigueStress concentrations are the dominant driver of fatigue crack initiation. This guide explains how to identify, quantify and assess them using Kt, Kf and FEA stress.How to Convert a Load History into Fatigue CyclesReal service loading is a time history, not a set of constant-amplitude cycles. This guide explains cycle counting using the rainflow method and building a fatigue spectrum.
Dynamics & Vibration
How to Perform a Modal AnalysisModal analysis extracts the natural frequencies and mode shapes of a structure. It is the foundation for all dynamic response analyses.How to Check Modal Effective Mass for Dynamic AnalysisEffective mass tells you whether you have extracted enough modes. This guide explains what it means and how to use it.How to Perform a Random Vibration AnalysisRandom vibration analysis predicts the structural response to stochastic excitation using PSD input and modal superposition. This guide explains the complete workflow.How to Interpret a Power Spectral Density (PSD)A PSD describes how random vibration energy is distributed across frequency. This guide explains how to read, check and use a PSD correctly.How to Choose Structural DampingDamping has a strong effect on dynamic response, but choosing the right value is difficult. This guide explains the options and provides practical guidance.How to Perform a Frequency Response AnalysisFrequency response analysis predicts the steady-state response of a structure to harmonic excitation across a frequency range. This guide explains the setup and interpretation workflow.How to Calculate the RMS Response from a Random Vibration AnalysisThe RMS response is the single-number measure of random vibration severity. This guide explains how to extract, verify and interpret it.
Composites
How to Model Composite Layups in FEAAccurate composite laminate modelling requires careful material card definition, ply stack input and verification of the ABD matrix. This guide provides the complete workflow.How to Interpret Composite Failure CriteriaComposite failure criteria predict first-ply failure, but interpretation requires understanding what each criterion measures. This guide explains the common criteria.How to Select Ply OrientationsPly orientation determines how the laminate carries load. This guide explains the practical rules for selecting a balanced, manufacturable layup.How to Define a Composite Laminate SpecificationA laminate specification is the engineering document that defines the ply stack for manufacture and analysis. This guide explains what to include and how to verify it.
Thermal & Multiphysics
How to Perform a Steady-State Thermal AnalysisSteady-state thermal analysis predicts the temperature distribution in a structure under constant thermal loads. This guide explains the setup and verification workflow.How to Apply Thermal Loads to a Structural ModelConverting a temperature field into structural loads requires correct mapping and coefficient of thermal expansion definition. This guide explains the workflow.How to Decide Whether Coupled Analysis Is RequiredCoupled thermo-mechanical analysis is expensive. This guide explains when it is needed and when a sequential (uncoupled) approach is sufficient.How to Perform a Thermal Stress AnalysisThermal stress analysis combines a temperature field with structural constraints and material properties to predict deformation and stress from thermal loading.
Verification & Correlation
How to Perform a Free-Body Check on an FE ModelThe free-body check confirms that loads and reactions are in equilibrium. This guide explains how to perform it and what to do when it fails.How to Compare FEA with Hand CalculationsHand calculation correlation is the most accessible independent check of FEA results. This guide explains how to select the right check and interpret discrepancies.How to Investigate Unexpected FEA ResultsWhen FEA results do not match engineering expectation, a systematic investigation identifies the cause. This guide provides the diagnostic workflow.How to Document Model AssumptionsUndocumented assumptions cannot be reviewed or challenged. This guide explains what to document and how to present it in the analysis report.
Seismic
How to Apply a Floor Response SpectrumThe procedure for taking a floor response spectrum (FRS) and extracting modal accelerations for equipment mounted at an elevation — from input validation through modal combination to recovered acceleration for qualification.How to Perform a Modal Response Spectrum AnalysisThe complete workflow for modal response spectrum analysis — from model preparation and modal extraction through spectral acceleration lookup, modal combination and directional combination to recovered structural response.How to Select Damping for Seismic AnalysisHow to choose the correct damping ratio for seismic response spectrum analysis — considering material, structural system, stress level and code provisions — and how to apply it consistently across the spectrum and the model.How to Check Effective Modal Mass for Response Spectrum AnalysisHow to compute, interpret and use effective modal mass to determine whether enough modes have been extracted for a seismic response spectrum analysis — including cumulative mass thresholds and missing-mass correction.How to Decide Between SRSS and CQCHow to determine whether the Square Root of Sum of Squares or the Complete Quadratic Combination method is appropriate for combining modal responses — based on modal frequency spacing, damping and structural configuration.How to Combine Seismic DirectionsHow to combine the responses from orthogonal seismic directions — the 100-40-40 rule, SRSS directional combination and the statistical basis for each — to produce a single enveloped response for assessment.How to Recover Forces from Response Spectrum AnalysisHow to recover element forces, beam forces, shell resultants and support reactions from a modal response spectrum analysis — including the correct order of modal and directional combination for force quantities.How to Recover Stress from Response Spectrum AnalysisHow to recover stress components from a modal response spectrum analysis — the correct procedure for combining stress components across modes and directions, and the critical question of how to compute equivalent (von Mises) stress from combined components.How to Assess Cabinet Seismic ResponseHow to assess the seismic response of electrical and control cabinets — from modelling the frame and panels through modal analysis and floor response spectrum application to the evaluation of structural integrity and functional performance.How to Model Equipment Mass for Seismic AnalysisHow to represent equipment mass in a seismic FEA model — lumped vs distributed mass, mass moments of inertia, off-centre mass and the effect of mass representation on modal frequencies and recovered accelerations.How to Assess Seismic AnchorageHow to assess the seismic capacity of anchor bolts, welds and holding-down arrangements — from recovering seismic anchor loads through capacity checks for tension, shear and combined loading to concrete failure modes.How to Perform Seismic Analysis in NastranHow to set up and run a seismic response spectrum analysis in MSC Nastran — from modal extraction through the SOL 200 response spectrum analysis to force and stress recovery, with the specific Nastran cards and parameters.How to Perform Response Spectrum Analysis in AnsysHow to set up and run a seismic response spectrum analysis in Ansys Mechanical — from the modal analysis through the spectrum definition and combination to stress recovery, with the specific Ansys settings and post-processing steps.How to Correlate Seismic FEA With Shake-Table TestingHow to correlate analytical seismic response predictions with shake-table test results — from test instrumentation planning through model updating to assessing the level of agreement and explaining discrepancies.How to Review a Seismic AnalysisHow to perform an independent technical review of a seismic response spectrum analysis — the checklist of items to verify, the common errors to look for and the acceptance criteria for signing off the analysis.How to Build a Defensible Seismic Qualification ReportHow to assemble a seismic qualification report that withstands regulatory and customer scrutiny — the required sections, the evidence chain from input to margin, and the documentation standards for traceability and defensible engineering judgement.
Turbomachinery
How to Apply Centrifugal Loading in FEAStep-by-step guide to defining rotational body loads, verifying the centrifugal resultant and checking stress against analytical estimates for turbomachinery components.How to Analyse a Turbine BladeComplete workflow for turbine blade structural analysis — from geometry and loads through centrifugal, aerodynamic, thermal, modal and fatigue assessment.How to Analyse a Rotating DiscWorkflow for rotating disc structural analysis — geometry, centrifugal load, blade pull, thermal stress, bore stress and fatigue assessment.How to Model a Fir-Tree Blade RootStep-by-step guide to building a nonlinear contact FEA model of a fir-tree blade root attachment, including mesh, contact, friction and post-processing.How to Perform Pre-Stressed Modal Analysis of a Rotating BladeStep-by-step guide to pre-stressed modal analysis — applying centrifugal pre-stress, extracting frequency vs speed and building the Campbell diagram.How to Build a Campbell DiagramPractical guide to constructing a Campbell diagram from pre-stressed modal analysis results and identifying resonance crossings with engine order excitations.How to Assess Turbomachinery OverspeedStep-by-step guide to overspeed analysis — nonlinear elastic-plastic FEA, clearance check, structural margin and reporting for the overspeed condition.How to Perform Turbomachinery Cyclic-Symmetry AnalysisGuide to setting up cyclic symmetry models — sector definition, boundary conditions, static and modal analysis, and interpreting nodal diameter results.How to Review a Turbomachinery Structural AnalysisStructured review process for turbomachinery structural analysis reports — checking loads, models, verification, margins and completeness.
Buckling & Stability
How to Perform an Euler Buckling CheckStep-by-step guide to calculating the Euler critical load for a slender column, selecting the effective length, checking slenderness and interpreting the result.How to Calculate Column SlendernessPractical guide to computing slenderness ratio, radius of gyration and transition slenderness, and determining whether Euler or inelastic buckling governs.How to Perform Plate Buckling AnalysisWorkflow for plate buckling assessment — from geometry and loading through critical stress, interaction equations and post-buckling consideration.How to Perform Eigenvalue Buckling in FEAStep-by-step guide to setting up, running and interpreting a linear eigenvalue buckling analysis — from pre-stress through mode extraction and load factor interpretation.How to Introduce Geometric Imperfections into a Buckling ModelGuide to seeding nonlinear buckling models with geometric imperfections — eigenmode-based, measured, and equivalent imperfection approaches.How to Perform Nonlinear Buckling AnalysisComplete workflow for nonlinear buckling FEA — from imperfection seeding through load stepping, arc-length control, collapse prediction and interpretation.How to Assess Shell BucklingPractical workflow for shell buckling assessment — geometry, loading, imperfection sensitivity, analysis method selection and collapse prediction.How to Assess a Stiffened PanelWorkflow for stiffened panel buckling assessment — skin buckling, stiffener stability, post-buckling reserve, crippling and collapse prediction.How to Review a Buckling AnalysisStructured review process for buckling analysis reports — checking loads, model, imperfections, analysis method, margins and engineering conclusions.
Pressure & Containment
How to Calculate Hoop Stress in a Thin-Walled CylinderStep-by-step guide to deriving and applying the hoop stress formula for a thin-walled cylindrical pressure vessel, including variable definitions, units and verification.How to Calculate Longitudinal Pressure StressStep-by-step calculation of the axial membrane stress in a closed-ended cylinder from the pressure end load, including open-ended and closed-ended cases.How to Calculate Pressure End ThrustStep-by-step calculation of the pressure thrust force on end closures, flanges and pipe terminations, with worked substitution and verification.How to Assess a Thick-Walled CylinderStep-by-step guide to using the Lame equations for thick-walled cylinder stress analysis, including internal, external and combined pressure cases.How to Apply Pressure Loads Correctly in FEAStep-by-step guide to applying pressure as a surface load in FEA, verifying the pressure resultant, checking surface normals and confirming equilibrium.How to Model a Pressure Vessel Nozzle in FEAStep-by-step guide to building a nozzle FEA model — solid elements, mesh refinement, pressure and piping load application, and stress linearisation.How to Check Pressure-Model EquilibriumStep-by-step equilibrium verification for pressure vessel FEA — pressure resultant, end thrust, support reactions, moment balance and common errors.How to Perform an External-Pressure Buckling AssessmentStep-by-step workflow for assessing cylindrical shells under external pressure — eigenvalue screening, imperfection modelling, nonlinear collapse analysis and margin assessment.How to Include an Imperfection in Collapse AnalysisStep-by-step guide to introducing geometric imperfections into nonlinear buckling analysis — mode-shape scaling, measured imperfections and sensitivity assessment.How to Perform Stress LinearisationStep-by-step guide to extracting membrane, bending and peak stress components from a pressure vessel FEA model using stress classification lines.How to Assess Pipe Pressure ThrustStep-by-step guide to calculating pressure thrust at pipe bends, closures, reducers and expansion joints, and assessing the resulting support and anchor loads.How to Review a Pressure & Containment AnalysisStructured review process for pressure and containment analysis reports — checking requirements, loads, models, verification, margins and completeness.
Probabilistic & Reliability
How to Define Random Variables for an Engineering ModelThe procedure for identifying which inputs in an engineering model should be treated as random variables, selecting their distributions and defining their parameters from data or engineering judgement.How to Select Probability DistributionsA structured procedure for choosing the appropriate probability distribution for an engineering variable — physics first, then data, then goodness of fit, then sensitivity.How to Perform Monte Carlo Structural AnalysisThe complete workflow for Monte Carlo simulation on a structural FEA model — from input distribution definition through automated execution to result extraction and failure probability estimation.How to Perform Latin Hypercube SamplingThe procedure for generating a Latin hypercube sample set for efficient uncertainty propagation — stratification, pairing and verification of sample coverage.How to Define a Structural Limit StateThe procedure for defining a limit-state function for structural reliability — identifying the resistance, the demand, the performance criterion and the safe/failure boundary.How to Perform a FORM Reliability AnalysisThe procedure for a First-Order Reliability Method analysis — transforming to standard-normal space, finding the design point, computing the reliability index and the failure probability.How to Perform Probabilistic Fatigue AnalysisThe procedure for probabilistic fatigue analysis — modelling S-N scatter, load uncertainty, fatigue-life distribution and the probability of fatigue failure before the design life.How to Update Engineering Predictions with Test DataThe Bayesian procedure for updating engineering model predictions using physical test measurements — prior, likelihood, posterior and updated predictions.How to Review a Probabilistic Reliability AssessmentA structured review procedure for a probabilistic reliability assessment — checking inputs, distributions, model verification, method, results, sensitivity and reporting.
Ballistics & Penetration
How to Build a High-Rate Impact FEA ModelThe complete workflow for building an explicit FEA model of a structural target under high-velocity impact — from geometry and material definition through contact, mesh and solver setup.How to Define Contact for Structural ImpactThe procedure for defining contact in explicit FEA for structural impact — algorithm selection, friction, penetration tolerance, erosion support and verification.How to Apply an Externally Specified Impact Velocity in Explicit FEAThe procedure for applying an externally specified impact velocity to a projectile or fragment in explicit FEA — initial conditions, velocity direction, mass definition and verification.How to Select a Mesh for Penetration AnalysisThe procedure for selecting and verifying a mesh for penetration analysis — local refinement, element size, through-thickness discretisation and mesh-sensitivity assessment.How to Check Energy Balance in High-Rate Impact FEAThe procedure for checking the energy balance in an explicit FEA impact analysis — what to look for, what is acceptable and what indicates a problem.How to Assess Residual Structural Strength After ImpactThe procedure for assessing the residual structural strength of a target after high-velocity impact — damage characterisation, remaining section, static analysis and inspection-informed reassessment.How to Correlate an Impact Model with TestThe procedure for correlating an explicit FEA impact model with a physical impact test — what to measure, what to compare and how to assess agreement.How to Review a Ballistic Structural AnalysisA structured review procedure for a ballistic impact structural analysis — checking inputs, model, verification, results, sensitivity and reporting.
Creep & High-Temperature
How to Determine Whether Creep is RelevantA structured procedure for assessing whether creep deformation needs to be considered in a structural analysis — based on homologous temperature, service duration, stress level and material type.How to Select a Creep ModelA procedure for selecting the appropriate creep constitutive model for a given material, temperature range, stress level and analysis duration.How to Calibrate a Norton Creep ModelThe procedure for fitting Norton creep law parameters from creep test data — extracting the minimum creep rate, fitting the stress exponent and activation energy, and verifying the fit.How to Perform Creep Analysis in FEAThe complete workflow for performing a creep analysis in finite element software — from thermal and structural model setup through creep law definition, time stepping and result extraction.How to Model Stress RelaxationThe procedure for modelling stress relaxation in components under imposed strain at high temperature — setting up the FEA, choosing between time-hardening and strain-hardening, and interpreting the relaxation curve.How to Assess Creep Rupture LifeThe procedure for assessing creep rupture life — using stress-rupture curves, Larson-Miller parameterisation, damage accumulation and remaining-life methods.How to Assess Creep-Fatigue InteractionThe procedure for assessing creep-fatigue interaction in components subjected to cyclic loading at elevated temperature with hold periods.How to Review a High-Temperature Structural AnalysisA structured review procedure for a high-temperature creep structural analysis — checking material data, model setup, creep law, convergence, results and reporting.
Random Vibration
How to Read a Random Vibration PSDA structured procedure for reading and interpreting a random vibration PSD specification — breakpoints, slopes, units, frequency range and Grms verification.How to Calculate RMS from a PSDThe procedure for integrating a PSD to obtain the RMS — for flat, piecewise and general PSD curves — with worked examples and resolution checks.How to Use Miles EquationA procedure for applying Miles equation to estimate the RMS response of an SDOF system under random excitation — when it is valid, how to apply it, and how to interpret the result.How to Set Up Random Vibration FEAThe complete workflow for setting up a random vibration analysis in commercial FEA software — from modal analysis through PSD input to response recovery.How to Select Modal Damping for Random VibrationA procedure for selecting damping values for random vibration analysis — sources, typical ranges, sensitivity studies and documentation.How to Perform Random Vibration Fatigue AssessmentThe procedure for assessing fatigue life under random vibration — from stress PSD through cycle distribution to damage accumulation and life prediction.How to Model Multiple Random InputsA procedure for setting up multi-input random vibration analysis — determining correlation, selecting the analysis approach and interpreting results.How to Verify a Random Vibration AnalysisA structured verification procedure for checking that a random vibration FEA analysis is correctly set up and producing plausible results.How to Review a Random Vibration Qualification AnalysisA structured review procedure for a random vibration qualification analysis — checking environment, PSD, modal basis, damping, response, fatigue, test plan and reporting.
Shock & Transient Dynamics
How to Read a Mechanical Shock SpecificationStep-by-step method for interpreting a mechanical shock specification — input form, axes, units, damping, bandwidth, acceptance outputs and qualification intent.How to Create an SRS from a Shock Time HistoryStep-by-step method for generating a shock response spectrum from a measured or specified time history, including damping, sampling, frequency spacing and convergence checks.How to Set Up Modal Transient AnalysisStep-by-step workflow for modal transient analysis — modal basis selection, damping, time-step control, response recovery and truncation verification.How to Set Up Direct Transient AnalysisStep-by-step workflow for direct transient analysis — model setup, damping, integration controls, time-step sensitivity, output recovery and numerical verification.How to Select a Time Step for Shock AnalysisPractical method for selecting and verifying the time step for shock and transient-dynamic analysis based on input bandwidth, retained modes and response resolution.How to Analyse a Half-Sine Shock PulseStep-by-step method for interpreting and analysing a half-sine shock pulse, including amplitude, duration, impulse, velocity change and structural response checks.How to Assess a Drop ShockPractical workflow for assessing drop shock — impact velocity, contact assumptions, pulse characterisation, structural response and correlation with test conditions.How to Correlate Shock Analysis with TestStep-by-step workflow for correlating shock analysis with test using time histories, SRS, modal behaviour, interface conditions and uncertainty evidence.How to Review a Shock Qualification AnalysisStructured review method for shock qualification analysis covering requirements, model fidelity, transient inputs, convergence, response recovery and evidence quality.
Advanced Damage & Failure
How to Select a Composite Failure CriterionA structured procedure for selecting the appropriate composite failure criterion based on mechanism, laminate, load case, design stage and available data.How to Set Up Progressive Composite Damage AnalysisA complete procedure for setting up a progressive damage analysis in commercial FEA — from model preparation through failure criteria to damage evolution and solver control.How to Distinguish Failure Initiation from Damage EvolutionA procedure for correctly interpreting failure predictions — distinguishing when damage begins from how it progresses and when the structure collapses.How to Model Delamination Using Cohesive ElementsA procedure for setting up cohesive-zone elements at ply interfaces to model delamination initiation and propagation in composite laminates.How to Select Cohesive-Zone Parameters from Test DataA procedure for calibrating cohesive-zone model parameters — strength, fracture energy, stiffness — from standard fracture and strength tests.How to Perform a VCCT Delamination AssessmentA procedure for using the Virtual Crack Closure Technique to assess delamination growth from a pre-existing crack in a composite laminate.How to Model Low-Velocity Impact on a Composite LaminateA procedure for setting up and running a low-velocity impact FEA on a composite laminate using explicit dynamics.How to Perform a Compression-After-Impact AnalysisA procedure for modelling the CAI test — from initial damage representation through compression loading to failure load prediction.How to Model a Composite Bonded JointA procedure for modelling bonded composite joints in FEA — adherend representation, adhesive cohesive zones, mesh and verification.How to Perform Mesh Sensitivity for Composite Damage AnalysisA procedure for checking mesh objectivity in progressive damage and cohesive-zone analyses.How to Correlate Composite Damage Analysis with TestA structured procedure for correlating composite damage FEA with test data — load-displacement, damage pattern, failure mode and ultimate load.