Abstract: This paper takes the runout of the composite reinforced stiffened panel as the object, and analyzes its mechanical properties in hydrothermal and normal environment through experiments. This paper describes the configuration, test plan, test process and test results. The results show that the hydrothermal environment has little effect on the stiffness of the structure, but has a certain influence on the strength. Therefore, the influence of the hydrothermal environment should be considered in the structural design.

Key words: composite materials, stiffened panels, runout, mechanical properties