Development of glass fibre reinforced composites using microwave heating technology

Fibre reinforced composites are differentiated by the used matrix material (thermoplastic versus duroplastic matrix) and the level of impregnation. Thermoplastic matrix systems get more important due to their suitability for mass production, their good shapeability and their high impact resistance. A challenge in the processing of these materials is the reduction of the melt flow paths of the thermoplastic matrix. The viscosity of molten thermoplastic material is distinctly higher than the viscosity of duroplastic material. An approach to reduce the flow paths of the thermoplastic melt is given by a commingling process. Composites made from commingling hybrid yarns consist of thermoplastic and reinforcing fibres. Fabrics made from these hybrid yarns are heated and consolidated by the use of heat pressing to form so called organic sheets. An innovative heating system is given by microwaves. The advantage of microwave heating is the volumetric heating of the material, where the energy of the electromagnetic radiation is converted into thermal energy inside the material. In this research project microwave active hybrid yarns are produced and examined at the Institute for Textile Technology of RWTH Aachen University (ITA). The industrial research partner Fricke und Mallah Microwave Technology GmbH, Peine, Germany develops an innovative pressing systems based on a microwave heating system. By implementing the designed microwave heating technology into an existing heat pressing process, FRTCs are being manufactured from glass and nanomodified polypropylene fibre woven fabrics. In this paper the composites are investigated for their mechanical and optical properties

An Electronic Osteosynthesis Implant for Continuous Load Monitoring using a Strain Gauge

The utilization of strain gauges for monitoring the applied mechanical load to osteosynthesis plates using electronic implants was reported several times in literature. The technique was found to provide valuable information for monitoring the fracture healing process and for improving the rehabilitation. This paper introduces a new electronic osteosynthesis implant, which uses supercapacitors as an energy storage for short term autonomous operation. Moreover, a bluetooth low energy (BLE) transceiver is integrated into the system, which covers larger distances and is less sensitive to misalignment than the commonly used inductive data transmission. This improves the usability of the proposed system for the patients. The system can continuously sample and transmit strain values at a sampling rate of 5 Hz for more than 10 min without being recharged. More than 60 cm of distance in any practically relevant direction can be covered by the BLE data transmission if the implant is placed 5 cm deep in a phantom. The implant dimensions of 20 mm x 16 mm still fit on osteosynthesis plates for larger bones

Development of Thermoplastic Composites for Visible Parts in Automotive

In order to reduce CO2 emissions, for the automotive industry, the most promising area of research is lightweight construction. Next to weight reduction, lightweight materials like fiber reinforced thermoplastic composites (FRTC) may also improve mechanical properties of vehicle body parts. FRTCs, so-called organic sheets, have the potential for large scale series production and they can be back moulded due to the thermoplastic matrix. On the other hand high production cycle times and a poor surface quality are limiting their potential. Therefore, ITA's current research approaches these problems in two ways. Nanomodified materials and a new tool concept for heat pressing are going hand in hand and may lead to the technology's breakthrough. To reduce the cycle times of the production of FRTCs innovative and modified matrix systems are investigated. The goal of the public founded project "VarioOrgano" is to analyze the potential of these modified yarns and the tool system during the FRTC production. Moreover, the capability of these composites in visible parts in automotive applications is investigated. Therefore, the whole process chain from compounding, to melt spinning, commingling and consolidation with a heat press is investigated. This paper shows the production steps along the process chain to produce these FRTCs with focus on hybrid yarn development and production