Abstract
An aluminum deck is fabricated by joining hollow extrusions with the friction stir welding (FSW). The purpose of this study is to understand the fatigue behavior of the deck. The material properties of the FSW region are investigated. A fatigue test is carried out for the deck, to show that a fatigue crack is initiated along the FSW-joining line of the top plate just under the load. The plate-bending stress produced by the local deformation of the top plate causes it. More fatigue tests are done for the beam-type specimens provided by cutting the deck in the transverse direction. The tests reveal that where the supporting interval of the deck becomes large, a fatigue crack is caused at the FSW of the bottom plate by the membrane stress due to the global bending moment, and that it propagates in the transverse direction to the FSW-joining line.
