The reduction of the direct operating costs of machines, structures and vehicles is pursued in numerous industrial sectors. Condition based maintenance, the scheduling of maintenance (intervals) on basis of continuous health information of the structure, can be a key enabler for these cost savings. The implementation of a robust and effective structural health monitoring (SHM) system provides the user with the required health information about the structure, but the implementation of the SHM system has even further potential in the creation of products with an increased added value for the customer; it results in an increased safety level, a higher reliability and employability of the machines, etc. By perfectly monitoring the “health” of the systems, a reduction of the total life cycle cost could also be aspired by enabling an easy implementation of life extension programs of the systems. Many SHM systems have been proposed in the past, but most of them have proven to be very sensitive to changing environmental conditions, accidental damage, false detections, grease, dirt and other polluting liquids, which resulted in very poor results when operated in the field.
The Brussels Acoustics and Vibration research group of the VUB has developed a robust and effective SHM system based on the new design freedom offered by 3D printing or additive manufacturing (AM) technologies. This design freedom enables the integration of 3D networks of capillaries in structural components. These capillaries are pressurized and the absolute fluid pressure in the closed 3D-curved network of capillaries is monitored. This SHM system can be used for crack monitoring, extensive wear monitoring and load (usage) monitoring. If complete 3D printing of the components is inappropriate, the monitoring channels can also be added with 3D printing on top of an existing structure, manufactured by conventional techniques.
The feasibility of the system has been demonstrated, extensively tested and is ready to be demonstrated on full scale applications.