Meaning
Conversion of plastic deformation work into thermal energy in solid materials determines the local temperature rise during rapid stretching. This thermodynamic parameter, known as the taylor quinney coefficient, defines the ratio of inelastic work that is dissipated as heat versus the energy stored in the material’s microstructure. It is critical for analyzing the localized self-heating of polymers under high-speed drawing.
Thermal Energy
During the rapid stretching of a preform, the mechanical energy supplied by the stretch rod is partially transformed into heat. With a high taylor quinney coefficient, the polymer experiences a significant localized temperature increase. This thermal energy lowers the local viscosity and yield strength of the polymer, allowing it to stretch more easily.
This heat-generating behavior can lead to localized thermal softening and altered stretching behavior during inflation.
Process Impact
Ignoring this self-heating effect in process simulations leads to an underestimation of the polymer temperature during blowing. This discrepancy causes the software to predict higher stretching forces than those observed in the actual machine. Accurate modeling of this thermal dissipation is necessary for the development of optimized preform designs.
Measurement Task
Determining this value experimentally requires high-speed infrared cameras and load cells to monitor temperature and stress simultaneously. These measurements are challenging because the temperature rise occurs over a few milliseconds. Accurate calibration of this coefficient improves the accuracy of process simulations.
