Numerical simulation of a resistant structural bonding in wind-turbine blade through the use of composite cord stitching

Fatigue Behavior of Smart Composites with Distributed Fiber Optic Sensors for Offshore Applications

“…It is noteworthy that strain values close to the edge were simulated so as to avoid FOS slippage and sensibility reduction. Finally, our research work highlighted the advantages of sinusoidal placement for large-scale wind-blades [1][2][3][4]. Previous works [1][2][3][4] also emphasized that straight FOS placement is of some interest for SHM of large wind turbine blades; one of its main drawback is the impossibility of measuring multiparameter strains, alongside the difficulty in identifying strain coordinates, especially when loading direction is random, which is typically the case of offshore farms (Figure 3).…”

“…Finally, our research work highlighted the advantages of sinusoidal placement for large-scale wind-blades [1][2][3][4]. Previous works [1][2][3][4] also emphasized that straight FOS placement is of some interest for SHM of large wind turbine blades; one of its main drawback is the impossibility of measuring multiparameter strains, alongside the difficulty in identifying strain coordinates, especially when loading direction is random, which is typically the case of offshore farms (Figure 3). More recently, dual-sinusoidal FOSs' placement (Figure 4) was shown to be a more promising strategy as it can provide strain signals in longitudinal as well as in lateral directions, thus, easing monitoring bending and torsion loadings simultaneously.…”

“…Accordingly, they expect maintenance and verification processes in a certain interval of time. Within EVEREST Project, previous research have shown that smart composites can be appropriate structural materials for future wind turbines with length beyond 100 m [1][2][3][4]. Maintenance works of these structures are conducted by nondestructive testing (NDT) in most of the times [1].…”

“…The sensors are used to provide the information about intrinsic material properties [2]. Fiber optic sensors (FOSs) were proved as a reliable choice for SHM of composites from previous studies [3,4]. They have a high confidence level to sense the microscale strains in composites.…”

“…Another point of great importance is related to placement of sensors within composites and bond joints. Two main solutions have been imagined and finely simulated elsewhere [1][2][3][4]; namely, placing FOS straight parallel to bonded joints and a placement where a sinusoidal fiber is covering the largest part of bond joint surfaces and/or plies (Figure 2). As the bond joints are wide, many parallel FOS are needed for fine monitoring and this is particularly costly since many optical back-scattering apparatuses, OBRs, are needed.…”