ABSTRACT Epoxy resins are widely used in aerospace and automotive manufacturing as structural adhesives and matrices for carbon fiber–reinforced polymers (CFRPs), but their curing is often time‐consuming and sensitive to processing conditions. This study investigates the influence of ultrasonic energy on epoxy resin curing and demonstrates continuous, non‐destructive monitoring of cure progression using impedance spectroscopy over a relevant frequency range. While conventional approaches using temperature measurements combined with cure‐kinetics models already allow accurate estimation of the degree of cure, dielectric measurements provide a direct, continuous, and non‐destructive probe of the evolving material state through changes in capacitance and resistance. These dielectric parameters were correlated with a cure kinetics model, validated by DSC, enabling accurate mapping of the time‐dependent evolution of degree of cure, even at low ultrasound power levels, where the effective reaction rate is increased without altering the cure kinetics model structure. Experiments in an ultrasonic bath show that mechanical vibrational energy accelerates cure primarily through localized heating within the resin, rather than through bulk conductive heating of the sample arising from the ultrasonic equipment, which has been the dominant effect reported in previous studies. The results highlight the potential of ultrasound‐assisted curing combined with in situ impedance monitoring to reduce curing time, mitigate defect formation, and improve process control in CFRP manufacturing.
Csehngeri et al. (Thu,) studied this question.