Sensor integration within composite structures for continuous load monitoring

Composite structures show a very complex mechanics and requires to pass trough a very strict design and challenging maintenance tasks. To relax design and maintenance constraints, structural health monitoring and load monitoring have been increasingly investigating for decades. Nonetheless, there is still a gap between scientific results and industry deployment due to different aspects such as sensors' equipment costs, manufacturing costs, durability and reliability of the integrated structure. This paper deals with the integration of commercially available strain gauges within composite structures in view of low cost system for continuous load monitoring. The manufacturing process has been controlled opportunely to succesfully embed sensors among different plies. Several tests have been carried out to investigate the effect of the insert on the durability of components and the reliability of the monitoring system approaching linear and non-linear behaviour of structures. The results shows that integrating sensors in composite specimen could even benefit the stiffness of the overall section. However, the thoughness of the material is affected negatively, compromising the durability. Nonetheless, the changes respect to pristine configuration are compensated by the benefit of integrating sensors within the structure. In addition data can be stored to fatigue record and may also be used to warn the occurrence of a damage whether due to the insert induced discontiuity or to the excessive load achieved.