Deformation Characterization of Friction-Stir-Welded Tubes by Hydraulic Bulge Testing

Welding is playing a growing role in transport industry due to relevant advantages it allows. Friction Stir Welding is considered one of the most promising joining technologies, especially when it is applied to light alloys. Focusing attention on FSW of T-joints, several parameters have to be considered, and due to thermo-mechanical features of process, T joints need a dedicated approach. A set of previously developed experiments has shown that the tilt angle plays a relevant role in the joint strength. Furthermore it should be observed that T-joints are very often utilized in aerospace industries since the produced structures are composed of joined skins and stingers. Numerous data are reported in literature about FSW of butt joints, very few data, to authors’ knowledge, exists on T joints. In this paper a micro structural and mechanical analysis has been developed on FSW T-joints of AA 6082 T6 rolled plates, realized setting welding direction both parallel and perpendicular to rolling direction. The obtained results can be considered as a further acquired knowledge in the comprehension and the design of FSW processes.

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HYDRAULIC BULGE TESTING TO COMPARE FORMABILITY OF CONTINUOUS AND STRETCH BROKEN CARBON FIBER PREPREG LAMINATES

10.12783/asc36/35953 ◽

2021 ◽

Author(s):

YONI SHCHEMELININ ◽

JARED W. NELSON ◽

ROBERTA AMENDOLA

Keyword(s):

Carbon Fiber ◽

High Strength ◽

Biaxial Stress ◽

Fiber Reinforced Polymer ◽

Aviation Industry ◽

Strain Behavior ◽

Reinforced Polymer ◽

Fiber Reinforced Polymer Composites ◽

Bulge Testing ◽

Hydraulic Bulge

The use of carbon fiber reinforced polymer composites has increased with the increased need for high-strength, low-density materials, particularly in the aviation industry. Stretch broken carbon fiber (SBCF) is a form of carbon fiber created by the randomized breaking of aligned fibers in a tow at inherent flaw points, resulting in a material constituted of collimated fiber fragments longer than chopped fibers. While continuous carbon fibers possess desirable material properties, the limited formability prevents their wider adoption. SBCF composites exhibit pseudo-plastic deformation that can potentially enable the use of traditional metal forming techniques like stamping and press forming well established in mass production applications. To investigate the formability of SBCF composites prepared with either continuous or stretch broken Hexcel IM-7 12K fiber, impregnated with Huntsman RDM 2019-053 resin, hydraulic bulge testing was performed to explore the strain behavior under biaxial stress conditions at elevated temperature under atmospheric pressure. Initial results show better formability of SBCF compared to continuous fiber, characterized by the axisymmetric response to the applied stress.

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