Shape sensing of composite shell using distributed fibre optic sensing

Shape sensing is critically important throughout the lifecycle of composite shell structures, including the design, manufacturing, service, retirement, and reuse phases. In the service phase, for instance, shape-based structural integrity assessments can inform maintenance strategies, significantly reducing regular maintenance costs. To achieve high-fidelity shape sensing, a novel approach is proposed for strain acquisition and interpolation in carbon fibre reinforced polymer (CFRP) shell structures, utilizing distributed fibre optic sensing. This method is designed to enhance the performance of the inverse finite element method (iFEM). The approach introduces a new strain acquisition strategy based on distributed fibre optic sensors and a strain interpolation technique leveraging single image super-resolution (SISR). In the strain acquisition process, a fundamental sensing block capable of capturing both normal and shear strain is employed for sensor network design, which can be easily implemented using fibre optic sensors. The goal of this acquisition strategy is to standardize sensor network design and provide a digital representation, offering novel insights into shape reconstruction for different composite shells across various applications. Utilizing the obtained strain field, the SISR-based strain interpolation method generates a displacement field with enhanced spatial resolution through iFEM. Experimental evaluation of the SISR-based interpolation demonstrates its efficacy in capturing high-fidelity displacement fields in both smooth and non-smooth strain regions of CFRP shell structures. The introduction of SISR in strain field interpolation, for the first time, offers a potential solution to the challenge of interpolating non-smooth strain fields, providing a reference for addressing complex strain field interpolation in practical applications.