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Modern Group

R&D · Product Development

Thermal and Structural Analysis of Automotive Headlamps

Our CAE unit combines conjugate CFD with finite element analysis to predict, explain, and fix overheating, resonance, and overstress in lamp assemblies before the first prototype is built.

Headlamp assembly CAD model, rear and front views, used for the simulation
Headlamp assembly geometry used for the simulation.

Three analyses, one model

  • Thermal01

    Conjugate CFD

    Conduction, natural convection, radiation

  • Modal02

    Natural frequencies

    Resonance under operational vibration

  • Stress03

    Finite element analysis

    Stress distribution and durability

What We Analyse

Heat, Vibration, and Stress, Analysed Together

A headlamp brings heat sources, plastic components, and trapped air together in a compact, enclosed space, while also having to withstand road-induced vibration and mechanical loads. We perform thermal and structural analyses in parallel to evaluate all three factors in a single, integrated design review.

01

Thermal analysis

Heat is transferred by thermal radiation from hot surfaces, natural convection of heated air within the housing, and conduction through contact with adjacent hot components. Thermal analysis evaluates temperature distribution and identifies potential hot spots to prevent overheating and material damage.

02

Modal analysis

Identifying natural frequencies and mode shapes to assess the vibration behaviour of lamp assemblies and identify potential resonance risks under operational and road-induced vibration. This helps optimise structural stiffness and reduce excessive vibration and fatigue-related damage.

03

Stress and fatigue analysis

Evaluating stress distribution, stress concentrations, and structural deformation under mechanical and thermal loads to assess the integrity and durability of headlamp assemblies. This helps identify potential failure locations and improve reliability under demanding operating conditions.

01 / 03

Our Thermal Analysis Workflow

Our thermal analysis workflow evaluates the thermal behaviour of components and systems under specified operating conditions. It identifies temperature distributions, heat transfer mechanisms, and potential thermal issues, supporting design optimisation, better thermal performance, and reliable operation.

  1. Step 01

    Geometry Preparation and Model Simplification

    We review the CAD geometry and simplify the model while preserving the features that significantly influence heat transfer, including critical interfaces, contact surfaces, thin sections, and regions exposed to thermal loads.

  2. Step 02

    Material Properties and Thermal Boundary Conditions

    We define the relevant thermal properties, including thermal conductivity, specific heat capacity, and density, as required by the selected analysis. We also establish appropriate thermal boundary conditions, such as prescribed temperatures, heat fluxes, heat generation, convection, and radiation, to represent the intended operating environment.

  3. Step 03

    Finite Element Modelling and Mesh Generation

    We develop the finite element model and generate a suitable mesh to capture temperature gradients and heat transfer behaviour. Mesh refinement is applied in critical regions where steep thermal gradients or localised heat transfer effects are expected, and mesh quality is assessed to support reliable numerical results.

  4. Step 04

    Thermal Analysis Setup

    We configure the thermal analysis based on the physical problem and operating conditions. Depending on the application, we perform steady-state thermal analysis to determine temperature distributions under equilibrium conditions, or transient thermal analysis to evaluate temperature changes over time.

  5. Step 05

    Solving and Thermal Results Evaluation

    We solve the finite element model to determine the temperature field and relevant heat transfer parameters. The results are evaluated to identify hot spots, temperature gradients, heat flux paths, and regions with potentially inadequate thermal performance.

  6. Step 06

    Thermal Performance Assessment

    We compare the predicted temperatures and heat transfer results with material temperature limits, operating requirements, and applicable design criteria. Where relevant, we assess thermal expansion effects and temperature-induced stresses through coupled or sequential thermal-structural analysis.

  7. Step 07

    Design Optimisation and Final Reporting

    We identify opportunities to improve thermal performance through geometry changes, material selection, insulation, cooling strategies, or adjustments to boundary conditions. Finally, we document the analysis methodology, modelling assumptions, thermal results, critical regions, and engineering recommendations in a comprehensive technical report.

Results

What the results show

Numerical values and scales are omitted.

Surface temperature map of a headlamp, front and rear views
Surface temperature distribution, front and rear views. Shows the temperature across the solid components and highlights areas of higher thermal stress. Blue marks cooler regions and red hotter ones.
Mid-plane air temperature map with flow vectors around the optical module
Air temperature and flow vectors, mid-plane. Shows how heat builds up around the optical module and reaches the plastic components next to it.
Mid-plane air velocity map showing recirculation inside the lamp
Air velocity and recirculation, mid-plane. Slow zones hold hot air and show where venting or shielding helps most.
Temperature of two reflector bodies and their connectors
Temperature of the reflectors and their connectors. Shows how heat spreads through the reflector bodies and where the attached connectors stay cooler.
Air velocity vectors rising around a halogen bulb
Air velocity vectors around the lamp. Shows the natural convection pattern that rises from the lamp and carries heat into the adjacent parts.

03 / 03

Our Stress and Fatigue Analysis Workflow

Our stress and fatigue analysis workflow evaluates structural integrity under applied loads and predicts fatigue performance under repeated or fluctuating loading. It identifies critical stress concentrations, assesses potential failure locations, and estimates component durability over its service life.

  1. Step 01

    Geometry Preparation and Model Simplification

    We review the CAD geometry and simplify the model while retaining critical features such as holes, fillets, notches, joints, and other geometric discontinuities that may influence stress concentrations and fatigue performance.

  2. Step 02

    Material Properties and Loading Conditions

    We define the relevant material properties, including elastic and, when required, plastic behaviour, yield strength, ultimate tensile strength, and fatigue data. We also establish the applied loads, moments, pressures, contact conditions, and boundary conditions based on the intended operating environment.

  3. Step 03

    Finite Element Modelling and Mesh Refinement

    We develop the finite element model and refine the mesh in critical regions where high stress gradients or stress concentrations are expected. Mesh quality and convergence are evaluated to improve the reliability of the calculated stresses.

  4. Step 04

    Static Structural and Random Vibration Stress Analysis

    We perform structural analysis to determine the stress and deformation fields under the specified loading conditions and base excitation. Depending on the application, we evaluate von Mises stress, principal stresses, shear stress, displacement, and other relevant mechanical response parameters.

  5. Step 05

    Critical Stress Identification and Strength Assessment

    We identify critical regions and compare the calculated stresses with appropriate material strength limits and design criteria. Where applicable, we evaluate yielding, local stress concentrations, and the structural factor of safety.

  6. Step 06

    Fatigue Life and Damage Assessment

    We evaluate fatigue performance under repeated or fluctuating loads using an appropriate fatigue assessment method. Depending on the loading characteristics and available material data, we apply the stress-life (S–N) method. Mean stress effects, notches, and cumulative damage may also be considered where relevant.

  7. Step 07

    Design Optimisation and Final Reporting

    We identify opportunities to improve structural strength and fatigue resistance through geometry optimisation, stress concentration reduction, material selection, or changes in loading and support conditions. The final report summarises the analysis methodology, assumptions, stress distribution, critical locations, estimated fatigue life, and engineering recommendations.

Results

What the results show

Numerical values and scales are omitted.

Low-beam reflector

Equivalent von Mises stress across a low-beam reflector
Equivalent (von Mises) stress
Total deformation of a low-beam reflector
Total deformation

Housing

Equivalent von Mises stress across a headlamp housing
Equivalent (von Mises) stress
Total deformation of a headlamp housing
Total deformation
Development ProcessWhere CAE sits in lamp developmentAPQP and the V-Cycle, from requirements and feasibility to verification, tooling, and PPAP.Read the process

Business Inquiry

Validate a lamp design before tooling

Contact Modern Group to discuss thermal, modal, or stress and fatigue analysis for a lighting programme.

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