| Friction Stir Welding (FSW) is an advanced welding technology for joining materials using friction energy alone.;In the test program the static strength of FSW stiffened panel structures fabricated from 2024-T3 and 7075-T6 were compared with values from the reference literature. In addition, 20 fatigue test specimens classified into 5 groups according to the existence of a tool pin hole and the welding sequence. The welding sequences considered were: Single Pass, Double Pass (Type I) and Double Pass (Type II). S-N curves, fatigue crack growth rate data and metallurgical analysis were investigated and presented for the five groups of FSW specimens. It was found that the pin plunge and removal locations were key crack initiation points for specimens with discontinuous welding. However, the Double Pass (Type II) welding specimens with continuous welding showed outstanding fatigue life.;In this thesis, the FSW process was reviewed, and compared with other joining methods. In particular, the FSW process is considered as a manufacturing process for airframe structures. To this end a lap joint specimen was developed to represent the stiffened panel of an aircraft skin and its associated stiffener. The materials used in this test program were 2024-T3 as the skin and 7075-T6 as the stiffener. The skin and stiffener were joined using FSW. |
