Structural Health Monitoring of Composite Leaf Spring Using Guided Elastic Waves

The integration of advanced materials, such as fiber-reinforced composites, has transformed numerous industries by offering lightweight and high-performance solutions. In the context of automotive applications, these composites enable producing more efficient vehicles. Nevertheless, there are still uncertainties regarding operational safety. Potential emergence of barely visible damages such as fiber fracture, delamination and debonding account for a limited lifespan of the composite components. To address these concerns, permanent monitoring offers a compelling solution, enabling the early detection of damage, thus reducing maintenance costs and the risk of failures that could affect human life. In this case, guided waves based Structural Health Monitoring (SHM) has demonstrated promising results. However, it has so far primarily remained in laboratory settings with limited real-life applications due to some challenges, such as the costs involved and the transparency of results. This contribution focuses on the development of permanent monitoring of a novel leaf spring component manufactured of a carbon and glass fiber-reinforced composite. To establish permanent structural monitoring, piezoelectric transducer arrays have been integrated into the composite leaf spring structure during manufacturing. The placement of these transducers is determined through sensitivity analysis, considering ultrasound wave propagation characteristics. After a series of measurements, state-of-the-art damage identification methods customized to designed SHM setup are employed and compared. Outcomes are discussed with an emphasis on the efficient detection of narrow body composite structures. Additionally, damage detection evaluation of low-sensitive areas in such structures are explored.While reliability assessment and compensation of environmental effects have been left for future research, this study presents tested methods and results, aiming to contribute to the advancement of SHM techniques in practical applications.