Diffusion Control Integration for High Temperature Thermoset Kinetic Calculations during Mold Cure
Integrating diffusion control into thermoset kinetic calculations prevents overestimating late-stage mold cure rates near vitrification.
Kinetic User Subroutine
Meaning
Custom software module written to define the rate of chemical reactions within a larger finite element simulation. This script governs the mathematical relationship between temperature, time, and the degree of cure for specific resin systems or adhesives. It stops applying when the simulation completes its final time step or the material reaches a fully cured state.
Rate Definition
Specific equations, such as the Arrhenius model, are coded into the program to describe how fast the material hardens. This kinetic user subroutine allows the simulation to handle proprietary materials that are not included in the standard software library. The capability of the model to reflect reality depends on the accuracy of the constants used in the script.
A pilot result from a simple thermal test is used to calibrate the subroutine before running a complex part simulation.
Numerical Integration
Calculation of the cure state happens at each node of the mesh during every increment of the simulation time. This process ensures that the local heat generation from the chemical reaction is accounted for in the overall thermal balance. The audit of the subroutine involves checking the output against known experimental data for the same resin.
Calling a simulation accurate without this validation leads to incorrect predictions of part quality.
Subroutine Interface
Communication between the main solver and the custom code must follow strict data structures to ensure stability. The software passes temperature and time information to the subroutine, which returns the current reaction rate. This loop continues until the entire part has been analyzed.