Strain testing of concrete using embedded fiber optic sensors in explosive testing

In order to measure the structural strain inside concrete under the impact of explosions and other strong shock loads, a flat-type multi-parameter distributed fiber optic sensor was developed. In this experiment, we employed distributed fiber optic sensing technology by deploying optical fibers at typical positions on the explosive model to monitor the real-time strain distribution of the structure under explosive impacts. Simultaneously, fiber optic grating sensors were embedded in the structure to accurately measure the strain parameters at specific locations. The experimental results demonstrate that the embedded distributed fiber optic sensors can accurately measure the internal strain of the concrete structure. The measured pit diameter on the target surface was 41cm, which is very close to the actual damage range (diameter of 37cm). The measured damage level also aligns with the actual damage level of the target. The fiber optic grating sensors, packaged with glass fiber-reinforced polymer (GFRP), exhibited stable measurements around 298με, which is almost identical to the distributed fiber optic measurement of strain at the center of the target, which was 253με. This technology overcomes the limitations of traditional measurement methods and is suitable for testing dynamic stress and strain under explosive impacts and in harsh environments with moisture and electromagnetic interference. It has excellent prospects for application.