Curie-supported accelerated curing by means of inductive heating - Part II Validation and numerical studies

Throughout the past, heating by electromagnetic induction has been frequently used to design speedier curing processes of adhesives. With this method, bonded components are exposed to an alternating electromagnetic field (EMF), which generates heat in EMF-sensitive adherends, like steel and aluminium, or in susceptors that are admixed to the polymers to be cured, e.g. fibres or particles. Recently, specially designed susceptors, so-called Curie particles (CP), have shown their great potential for induction curing. Heat generated in CP is capped by the materials Curie temperature (T-c), preventing the adhesive from overheating. As a result, curing proceeds way faster and independently from ambient temperatures, opening up new application fields for bonded components. Although practical applicability has already been demonstrated, CP-induced heating - and consequently curing - has proven to be very sensitive to the boundary conditions of the considered application. Therefore, induction times needed to achieve full cure must currently be determined by cumbersome and costly experimental investigations. To compensate for this disadvantage, the present study - representing the second part of a series - aimed at offering a first approach of a numerical model in which thermal and kinetic aspects of CP-induced accelerated curing were combined. For that, curing kinetics of two kinetically different 2K epoxy adhesives were linked to a transient heat flow simulation in Ansys based upon experimentally determined heat loads. Since the first part of this series concentrated on presenting all preliminary experimental work as well as analytics applied during modelling, this part focuses on the validation of the developed FEA using the exemplary application of CP-cured Glued-in Rod (GiR) specimens. In the following, various numerical parameter studies were carried out, demonstrating principal functionality of the new FEA technique and highlighting in particular its contribution for the design of more efficient and target-orientated CP-curing processes.