Thomas Heber

Design and testing of novel piezoceramic modules for adaptive thermoplastic composite structures

For the series production of adaptive fibre-reinforced thermoplastic structures, the development of process-adapted piezoceramic modules is gaining central importance. Therefore, thermoplastic-compatible piezoceramic modules (TPMs) are being developed which are suitable for a matrix-homogeneous adhesive-free integration of the modules in fibre-reinforced thermoplastic structures during a sequential hot-pressing process. Extensive numerical and experimental studies are available on the systematic development of the TPMs, whose thermoplastic carrier film, made, respectively, of polyetheretherketone (PEEK) or polyamide (PA), is already adapted to the matrix material of a thermoplastic composite structure and thus can be joined in a welding process without additional adhesives. The studies carried out indicate the influence of geometrical and technological parameters on the efficiency of consolidated and polarized TPMs and can thus be used to adapt the design specifications and process parameters of the TPMs. Besides these studies, a numerically based residual stress analysis shows the potential for a defined inducing of residual stresses in the TPM components.

Sensitivity analysis for the process integrated online polarization of piezoceramic modules in thermoplastic composites

The use of active composite structures in high-volume applications requires novel robust manufacturing processes as well as specially adapted functional modules. The paper presents actual research results with regard to the process-immanent polarization of novel thermoplastic-compatible piezoceramic modules (TPM) during the consolidation process of active fibre-reinforced thermoplastic composite structures. In particular the influence of varying manufacture process parameters of a hot-press process on the polarization behaviour is investigated. The main principal objective is the purposeful utilization of process parameters for polarization support.

Novel Repair Concept for Composite Materials by Repetitive Geometrical Interlock Elements

Material adapted repair technologies for fiber-reinforced polymers with thermosetting matrix systems are currently characterized by requiring major efforts for repair preparation and accomplishment in all industrial areas of application. In order to allow for a uniform distribution of material and geometrical parameters over the repair zone, a novel composite interlock repair concept is introduced, which is based on a repair zone with undercuts prepared by water-jet technology. The presented numerical and experimental sensitivity analyses make a contribution to the systematic development of the interlock repair technology with respect to material and geometrical factors of influence. The results show the ability of the novel concept for a reproducible and automatable composite repair.

Consolidation behaviour during manufacture of adapted piezoceramic modules for functional integrated thermoplastic composite structures

Abstract For the series production of adaptive fibre-reinforced thermoplastic structures, the development of process-adapted piezoceramic modules is gaining central importance. Thermoplastic-compatible piezoceramic modules are being developed which are suitable for a matrix-homogeneous adhesive-free integration of the modules in fibre-reinforced thermoplastic structures during a simultaneous welding process. Aiming at the continuous improvement of the novel module design and its manufacturing technology based on a hot-pressing technology, an adapted physical nonlinear simulation model was developed in order to analyze the material and process dependent function and consolidation behaviour. Special regard is given to residual stresses caused by different coefficients of thermal expansion of the component materials and their specific use to enhance the module performance.