Moisture Behavior of Aeronautic Carbon Fiber Reinforced Resin Composite Stiffened Panel

In order to investigate the moisture property of carbon fiber reinforced resin composite stiffened panel in hygrothermal environment, moisture experiments were conducted in condition of 70℃/85%RH. Stage moisture model was proposed and moisture behaviors were analyzed by finite element method. The results show that the moisture curve of experimental result agrees with Fick's diffusion law perfectly in initial moisture stage. However, stage moisture behavior exists in later moisture period. The moisture curve of stage moisture model agrees with finite element result,with an error less than 5% compared with the experimental result. The composite stiffened panel moisture mechanism is revealed by moisture concentration distribution. Additionally, the saturated moisture rate in different thickness zones is not synchronous, which is main reason resulting in stage moisture.