Induction Heating Simulations of Carbon Fabric-Reinforced Thermoplastics; On the Significance of Electrical Conductivity Characterisation
Sebastiaan van den Berg is a PhD student in the Department Production Technology. (Co)Promotors are prof.dr.ir. R. Akkerman and dr. M. Luckabauer from the Faculty of Engineering Technology.
Induction welding is a promising technique for assembling carbon fabric-reinforced thermoplastic composite aerospace components, owing to its potential for automation and ability to meet high production rate demands. This joining technique also reduces stress concentrations at the interfaces between the components in comparison to traditional joining techniques.
This work focuses on developing an accurate and computationally efficient simulation method for predicting temperature distribution within carbon fabric-reinforced thermoplastic composite laminates during induction heating. The method targets both process and structure design for induction-welded assemblies, necessitating a macroscopic laminate-level approach with homogenised material properties.
A key challenge identified was obtaining consistent, anisotropic electrical conductivity values for the inductively heated material. The development of a reliable method for measuring anisotropic electrical conductivity forms the foundation for the key findings of this study. A model representation on the composite laminate level was developed. Next, this laminate level homogenised anisotropic electrical conductivity is integrated into induction heating simulations, which are suited for the induction heating analysis of realistic composite structures.
The major result of this work is an approach to predicting heat generation during induction heating of arbitrary carbon fabric-reinforced TPCs. The proposed method involves first measuring the anisotropic electrical conductivity of the composite using the six-probe method. This measured electrical conductivity can then be incorporated into induction heating simulations by representing it as a function of the current direction. For quasi-isotropic laminates, it was found that the electrical conductivity description can be simplified to an isotropic representation based on measured electrical conductivity values. This simplification significantly reduces computational time while maintaining accuracy.
