Bolted connections on applications like infrastructure, mobility, energy generation, process industry and mining are exposed to high loads. Wear and tear and impacts from temperature variations or vibrations can decrease the stability of the jointed bolt connections. Regular inspection is therefore required for all relevant connections. The "Smart Screw Connection" enables wireless, self-powered monitoring of the preload force using a retrofittable sensor system for DIN bolts. A sensor measures the force on the bolted joint with the help of a piezoresistive thin-film layer. The data is processed and transmitted permanently to a cloud using the mioty® wireless protocol. The integration of energy harvesting technologies enables self-powered operation, whereby the electrical energy required can be generated from minimal temperature differences or using small solar cells on the system. Deviations in the preload force of bolted joints can thus be detected immediately by remote monitoring with the "Intelligent Screw Connection". In this way, downtime or maintenance can be reduced and serious damages will be avoided completely.
The Smart Screw Connection is a product of a joint initiative of 4 Fraunhofer Institutes within the Fraunhofer Cluster of Excellence Cognitive Internet Technologies CCIT.