03.55 · UV cure: does equal dose produce equal residual stress?

UV exposure, local conversion, heating and stress describe different parts of the same illustrative study. This exercise helps you distinguish incident exposure from the state reached through the thickness, and identify how illumination, geometry and the chosen material laws affect that state.

Open this exercise in Workbench

Prepare the baseline

Inspect wavelength, optical inputs, exposure schedule and the hypothetical material calibration before running. Make the requested intensity, sidedness, duration or thickness comparison without changing the remaining inputs. When comparing equal incident doses, retain the full time history instead of assuming that dose alone determines the response.

Worked procedure

1. Run 500 W/m² for 120 s, then compare a copy at 1000 W/m² for 60 s.

2. Both schedules have 60,000 J/m² incident dose. Extend both thermal cycles to the same final time and include cooling after the longer exposure.

3. Compare conversion profiles, exotherm, modulus evolution and final chemical-shrinkage stress at comparable cooled temperatures.

4. Explain any difference using nonlinear intensity dependence and temperature feedback; do not assume dose reciprocity.

Review checkpoints

Incident dose is intensity multiplied by exposure time; local absorbed dose varies with depth.

The supplied cycle ends at 300 s; extend it further if the laminate has not cooled near its reference temperature.

Model limits

Hypothetical UV-compatible composite; effective optics, kinetics, shrinkage and modulus require calibration. Carbon/epoxy source data do not prove UV transparency or compatibility. CLT includes thermal and post-gel chemical-shrinkage stress; distinguish peak stress from the cooled residual state. No fixtures, tool contact, oxygen transport, radical dark cure or viscoelastic relaxation. Not manufacturing validation.

Interpret the comparison

Read the intensity and conversion profiles together with temperature and any enabled stress components. Compare final stresses at comparable cooled states, and inspect the gel and modulus evolution used by the model. Refine the stated time and thickness controls before interpreting small differences; the current model’s dark-cure limitation must remain part of the conclusion.

How information passes between models

Micro → Laminates: Predicted ply stiffness, strength, density and expansion properties.

Materials → Micro: Constituent stiffness, strength, density and thermal / moisture properties.

Mechanical → Simulation: SIMULATION selects this case and its analysis model; the case owns its applicable cycle and input references.

Laminates → Mechanical: Ply angles and thicknesses, stiffness, mass and ply properties.

Geometry → Mechanical: Part shape and dimensions, thickness or section definition, and model-specific geometric inputs. Each selected case consumes only the dimensions its model supports.

Thermal → Simulation: SIMULATION selects this case and its analysis model; the case owns its applicable cycle and input references.

Laminates → Thermal: Ply angles and thicknesses, stiffness, mass and ply properties.

Equipment → Thermal: Linked lasers, IR/UV lamps, heaters, coolers and molds: dimensions, radiant power or prescribed temperature / heat flux, contact conductance, body and surface materials. Each boundary keeps its own placement, side and exposure.

Models → Micro: Applied model assignment: Halpin–Tsai. Model parameters and formulation are used by Micro.

Models → Mechanical: Applied model assignment: CLT · Linear static with failure indices. Model parameters and formulation are used by Mechanical.; Maximum stress

Models → Thermal: Applied model assignment: 1D transient heat transfer. Model parameters and formulation are used by Thermal.

Further reading and evidence

• Connect a simulation
• Cure exotherm and evolving modulus
• Run and review a model
• Review effective properties
• Enter a process cycle and boundary conditions
• Edit laminate materials, angles and thicknesses
• Connected inputs and result freshness
• Apply symmetry and balance
• Related case study: NASA process cure

Review the recorded validation scope. Retain the original inputs and solver notices with the results. Representative teaching data are not design allowables.