Study on the influence of transverse effect on strain monitoring of space station

The main tasks of the space station are to execute the manned space flight activities, scientific experiments, observation of astronomical phenomena, and maintenance of satellites for a long time. For a lot of scientific applications, it is necessary to increase the pressure in the cabin, which leads to the difference between the internal and external pressure. Then, the strain can be generated. The real-time and accurate monitoring of the strain on the cabin is one of the important factors to ensure the safety of astronauts. In China, it is the first time to measure the strain of the cabin by means of fiber Bragg grating (FBG) sensors. The optical fiber sensor has a measurement error of less than 4.52 is in the circumferential direction as compared with a resistance strain gauge acted as a reference. But the axial measurement error is very big, and the maximum is 28.93 mu epsilon. As a comparison, the strain of bare fiber in the axial direction is measured, and it is found that the error is terribly small. According to theoretical calculations, the transverse effect coefficient is 0.0271, and the experimental result is 0.0287. These two values are approximately consistent. By compensating the transverse effect of the FBG sensor, the measurement error is decreased by about one order of magnitude. It will be conducive to accomplish the health monitoring and condition assessment of space station.