Embedding rigid and flexible inlays in carbon fiber reinforced plastics

For producing Carbon Fiber Reinforced Plastics (CFRP) with desired mechanical and physical properties, it is essential to monitor the polymerization process. Therefore, sensors will be embedded in the composite in order to monitor temperature, pressure and/or curing index online. Inlays are foreign-objects in CFRP and behave as a wound in the composite. The composite may resist to foreign-objects. The impact of embedding sensors (inlays) on homogeneity and structural integrity of CFRP is not known yet. The aim of this study is to investigate the influence of embedding inlay on the mechanical properties of CFRP. Inlays of different materials from thick and rigid (silicon with different thicknesses) to soft and flexible (Polyimide and SU8) were embedded in the CFRP composite. These inlays are considered as embedded sensors for online monitoring. The impact of the inlay´s different sizes, types and patterns (existence of cavities) on composite were investigated by performing inter-laminar shear strength tests. The results of the inter-laminar shear strength tests clarified that not only can the flexibility of embedded sensors reduce the foreign-object effect of that in the composite, but also altering the size and substrate´s patterning can play an important role in improving the properties of composite with the embedded sensors.