An experimental program for evaluating the rotational capacity of aluminum
beams subjected to a moment gradient loading is presented. The study focuse
s on local buckling and on the tensile failure susceptibility. Results are
compared with design codes. Beams of different tempers, cross sections, and
lengths were tested. Some beams were welded, whereas others were unwelded.
Uniaxial tensile tests revealed a pronounced plastic anisotropy in the ext
ruded beams. Tests from the reduced strength zone near welds indicate a loc
al ultimate strength on the order of 67% of the parent material yield stren
gth in alloy AA 6082-T6. Nevertheless, the local failure mode is ductile. T
he strain-hardening behavior of the material and compressive flange width-t
hickness ratio have a strong influence on both the moment capacity and the
rotational capacity of aluminum beams. The magnitude of the moment gradient
has a significant influence on rotational capacity, whereas the effect on
the moment capacity is not very pronounced in the experiments. Welded membe
rs may suffer a tremendous loss of rotational capacity owing to premature t
ensile failure. Moreover, the tests provide a calibration basis for numeric
al modeling.