Abstract: In order to realize the effective connection between composite foam core sandwich tubes or between composite foam core sandwich tubes and other structures, a connection form of rib-stiffened flange is put forward, and integral molding composite foam core sandwich tube and rib-stiffened flange were produced by vacuum assisted resin introduction technique. Eccentric compression tests and cantilever lateral load tests were carried out on two-group specimens of composite foam core sandwich tube rib-stiffened flanges respectively. The loading process and failure mode were observed and the load-displacement curve was obtained. The results showed that when composite foam core sandwich tube rib-stiffened flange was under eccentric load, the failure mode of fiber compression fracture occurred in the transition position between stiffening ribs and sandwich tube body, and this position was the weak point of the specimen under eccentric compression. Under the effect of transverse load, the rib-stiffened flange was firstly subjected to fiber peeling failure of stiffening rib skin, then subjected to the fiber tensile failure at the connecting part of the composite flange and tube body. Finally, the flange of composite material appeared the failure of integral fold deformation. The failure process of flange has obvious characteristic of progressive failure.

Key words: composite foam core sandwich tube, rib-stiffened flange, eccentric compression test, cantilever test, failure mode