The Chinese space station is designed to carry out manned spaceflight, space science research, and so on. In serious applications, it is a common operation to inject gas into the hull, which can produce a strain of the bulkhead.

A space station is in-orbit for a long time and possesses many functions not possessed by manned spacecraft, such as airlock gas recovery technology. It is essential to disembogue the gas regularly in the cabin. A space station is generally made up of a rigid metal, so the operation of increasing pressure will cause the deformation of the bulkhead.

To monitor the deformation, a fiber Bragg grating (FBG) sensor is used to locate the specific position of the bulkhead to obtain the strain information. In serious applications, it was a common operation to inject gas into the hull, which can produce a strain of the bulkhead.

Accurate measurement of strain for the bulkhead is one of the key tasks in evaluating the health condition of the space station. This is the first work to perform strain detection for the Chinese space station bulkhead by using optical fiber Bragg grating.

In the period of measurements, the resistance strain gauge was used as the strain standard. The measurement error of the fiber optical sensor in the circumferential direction is very small, being less than 4.52 με.

However, the error in the axial direction was very large with the highest value of 28.93 με. Because the measurement error of bare fiber in the axial direction is tiny, the transverse effect of the substrate of the fiber optical sensor likely plays a role.

The comparison of the theoretical and experimental results of the transverse effect coefficients shows that they are fairly consistent, with values of 0.0271 and 0.0287, respectively.

After the transverse effect is compensated, the strain deviation in the axial detection is smaller than 2.04 με. It is of great significance to carry out a real-time health assessment for the bulkhead of the space station.

The space station has a long working cycle and needs to be filled with gas for daily life and scientific experiments. The FBG sensor was selected for the first time in the Chinese space station to monitor the strain of the cabin.

The resistance strain gauge was used as the strain measurement standard. The results show that the strain measurement of the FBG sensor and the resistance strain gauge are very close in the circumferential direction.

However, the absolute error is quite large in the axial direction. Adopting the axial compensation of the transverse effect coefficient, the absolute error is less than 3 με. These results are of great help to the test of force and the accurate assessment of the state in the cabin.