18th European Conference on Composite Materials (ECCM)
For the rework and the repair of thin-walled and complex shaped composite structures, a new approach based on adapted laser technology as well as piezo technique has been developed. Within the frame of the joint research project “ReWork” pulsed laser radiation is used to ablate the single layers of a CFRP structure. By a defined scanning of the laser beam across the surface, the carbon fibers and the matrix material are removed simultaneously. In this manner, damaged areas of the composite part are removed and the required stepped structure for a following patch insertion is realized. In order to provide highly accurate ablation profiles, the laser process is controlled by an inline measurement technology based on optical coherence tomography. Hereby the precision of the respective ablation depth is enhanced up to a deviation of less than 20 µm. The patch repair is accomplished by integrating piezo elements. Piezo actuators underneath the repair zone and on top of the integrated patch in conjunction with piezo sensors close to the repair patch at the surface of the original part are the basis for the monitoring of the consolidation phase. By providing tailored algorithms, a quantitative analysis of the curing progress as well as the resulting joint strength is realized.