Degree of Cure Definition for an Epoxy Resin Based on Thermal Diffusivity Measurements. (2016) - Rudolph, Martin
Abstract: This study deals with a novel measurement principle for the determination of the thermal diffusivity for a wide range of material classes and in addition with changing properties over time. For demonstrating purposes the curing reaction of an epoxy resin is exemplarily chosen. Basic idea is the evaluation of the difference between a purported temperature signal on one side of the specimen and the resulting temperature signal on the opposite side of it. The given signal is oscillating with low amplitude around the average measurement temperature. The two temperature profiles show differences concerning amplitude, mean value and phase. In order to determine the thermal diffusivity parameter (or material function in case of changing properties over time) a numerical modeling approach for the heat conduction problem and a subsequent parameter identification is presented within this paper. Modeling is based on the assumption of one-dimensional heat conduction. Moreover, detailed information on the specimen, the experimental setup, the measurements and the identification process is given. Finally, the obtained graphs for the evolution of the thermal diffusivity due to the chemical reaction of the epoxy resin are employed to define a degree of cure.