Structural shape reconstruction of fiber Bragg grating flexible plate based on strain modes using finite element method

摘要

Structural shape reconstruction plays an important role in structural health motoring, for example, in the fields of aerospace and civil engineering. A reconstruction algorithm is indispensable for structural shape reconstruction using discrete physical information. This article shows how to implement structural shape reconstruction using a small number of stain data measured by fiber Bragg grating sensors. First, the basic theory of structural shape reconstruction is introduced based on strain modes. A transformation from the measured discrete strain data to global displacement field is done by modal coordinate, which is the same for strain mode shape superposition and displacement mode shape superposition. Second, sensor layout optimization is carried out. Optimization analyses for the number of sensors and sensor position are implemented, and results show a better reconstruction effect for the optimized sensor layout. Meanwhile, effective parameters of the sensor layout are discussed, such as the excitation frequency, excitation amplitude, and number of mode shapes. Finally, structural shape reconstruction algorithm based on strain modes is applied in experiments. Static deformation and dynamic deformation tests are conducted to verify the proposed approach. Their results show that the reconstructed displacements match well with those measured by a laser displacement sensor.