The mechanical behavior of sandwich composite joints for ship structures

Low density foam core sandwich composites are recerving increasing attention and application in marine engineering. In order to solve the damage failure problem of sandwich L-joints for ship structures, the ultimate strength and fatigue properties of full scale L-joints were researched by experimental method. On the basis of the research on the static strength, the fatigue life and failure mode of this kind of connection were analyzed in different load amplitudes by a series of fatigue tests. The generation and development of cracks in the whole process were revealed and S-N curves were also drawn. The results show that fatigue life and stiffness of sandwich L-joints are decreased with the increase of load levels, and the major failure modes are in the form of sandwich debonding, sandwich face/core delamination, and gelcoat damage. Finally, a fatigue life model has been developed with stress level r and crack length ai and validated with test results.