Herstellung und Charakterisierung eines flexiblen kapazitiven Sensors für die Überwachung von kohlenfaservertärkten Polymeren

Abstract

The following thesis deals with the modeling, development and technology of a miniaturized interdigital sensor on flexible substrates to measure the degree of curing during manufacturing of the carbon fiber reinforced plastics. The special feature of the sensor is a very thin flexible substrate. Despite the small thickness, the film of the polyimide has a very good mechanical, thermal and chemical stability. This reduces the foreign body effect and makes it possible to leave the sensor in the compound material for long term use. The FEM simulations are used to calculate the sensor capacitance in the air and the sensitivity of the sensors to different types. In the technological implementation, all microsystem technology processes are realized on SI wafers. At the end of the manufacturing process, the flexible sensor of the second generation can be peeled off back from the silicon substrate. After the sensor characterization with different media the sensors with isolated electrodes are embedded in to CFRP. During the curing process, the implemented interdigital sensors provide the necessary data for online process monitoring. The complete curing of the CFRP plate is confirmed by using differential scanning calorimetry analysis. To demonstrate the secondary use of the flexible interdigital sensor in the context of structural health monitoring is proved the water intake of the CFRP plate with integrated sensor.