03.10 · Thermal cycle · surface/core lag

The environment’s temperature schedule and the temperature inside a laminate are not the same history. This exercise follows heat transfer through the thickness and, where enabled, the contribution from resin reaction heat, so that the surface and core can be interpreted as parts of one evolving process.

Open this exercise in Workbench

Prepare the baseline

Inspect the initial temperature, surface conditions, schedule and linked material data before running. Use the baseline to identify ramp, dwell and cooling intervals, then make the prescribed comparison while keeping unrelated parameters fixed. For a reaction-on versus reaction-off comparison, retain the distinction between a diagnostic calculation and a physically calibrated process model.

Worked procedure

1. Trace the thermal analysis to its laminate, Micro constituents and process cycle.

2. Run and inspect surface and core temperatures through the cycle.

3. Vary one film coefficient or dwell time, rerun, and compare the time required for the core to approach the target temperature.

Review checkpoints

Film coefficients are explicit inputs, not automatically inferred from a boundary label.

Record thermal conductivity, heat capacity and units used in the linked material models.

Model limits

One-dimensional through-thickness transport; lateral heat loss and oven airflow are not resolved. Inspect linked cure settings before interpreting reaction heating.

Interpret the comparison

Read the complete history rather than only the final contour. Compare core lag, internal peaks and gradients at stated times, and check the relevant temporal and thickness refinement. If residual stress is discussed, first establish the cooled reference state; a peak stress during processing is not necessarily the stress remaining after cooling.

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.

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.

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

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

Further reading and evidence

• Connect a simulation
• Edit material properties and units
• Enter a process cycle and boundary conditions
• Run and review a model
• Connected inputs and result freshness
• 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.