Failure of bolted connections in an aluminum alloy

In structures built from either pure aluminum or aluminum-base alloys, plates are often used as connecting elements. Design of connections necessitates that consideration be given to all aspects related to mechanical failure of the fastener, distress of material adjacent to the fastener(s), and net-section tensile failure, including tear out of the fasteners. The shear failure of aluminum alloy connecting elements is the focus of this paper. Aluminum alloy 6061 was chosen, and an experimental study was performed with the objective of rationalizing block shear failure in connecting elements. Gusset plates were chosen, and samples representing four different bolt patterns were mechanically deformed. Models to estimate the capacity of the joints are examined and compared with experimental results. Mechanisms governing damage and failure are highlighted in light of the competing influences of load/stress distribution and intrinsic microstructural effects.