Self-powered nanocomposite material detects its own cracks A vibration-powered CFRP composite with piezoelectric nanomaterials detects internal cracks via electrical changes, enabling self-powered, wireless structural health monitoring. (Nanowerk News) A new multifunctional composite made of carbon fiber-reinforced polymers (CFRP) and piezoelectric materials can use vibrations to self-detect tiny cracks. To make CFRP smarter, the researchers integrated a piezoelectric nanocomposite that converts mechanical energy into electrical energy. For practical use in aircraft and energy systems, the team used a lead-free piezoelectric material, potassium sodium niobate (KNN), instead of conventional lead-based ceramics. Under vibration, the material produced an open-circuit voltage of up to 13.6 V. More importantly, when artificial cracks were introduced between the CFRP and the piezoelectric nanocomposite layers, the output voltage and resonant frequency decreased as the cracks became longer.