Magnetostrictive materials and energy harvesting for structural health monitoring applications

Wireless sensors to monitor the state of the health of a civil structure could be widely adopted as a prompt and automatic solution to safeguard the cultural heritage and to guarantee safety. Nowadays, sensors are supplied by the electric grid or batteries, but in both cases some issues can occur. Batteries need to be recharged or replaced, thus increasing the operating cost of maintenance. The Energy Harvesting concerns with those actions focused on the exploitation of low-power, but widespread available, ambient energy sources, which otherwise would be normally wasted. In particular, the harvesting of vibrational kinetic energy could be a valid solution to the abovementioned problems, because of its large presence due to the anthropic activities and because it may overcome the strict rules to which historical sites often have to obey. Here a kinetic energy harvesting device based on magnetostrictives rods is presented. Its behavior is experimentally verified and discussed.