Effects of Hygrothermal Environment on Behavior of Composite Panel with PMI Foam

In this paper, the investigation on effects of hygrothermal environment on the bending behavior of composite panel with PMI foam is finished. The hat stringer panel is taken from composite rear pressure bulkhead of fuselage. The tests under room temperature and hygrothermal environment are carried out to verify the bending behavior of composite panel. The effect of bending behavior with 70 ℃ and 85% relative hygrothermal environment is discussed. The results show that the average failure load of hat stringer panel with PMI foam are decreased under upward and downward bending load. Besides, the hygrothermal environment has an influence on the failure mode of hat stringer panel with PMI foam. The failure mode of hat stringer panel with PMI foam alters from cracking of hat stringer to breaking of dome skin under the hat stringer. The results contribute to establishing the hygrothermal behavior assessment method of composite hat stringer panel with PMI foam.