TRANSVERSE STRAIN BEHAVIOR IN NO-2011 ALUMINUM-ALLOY SUBJECTED TO CYCLIC LOADING

This paper describes two independent series of tests that have been performed to measure dynamically the transverse strain behaviour of no. 2011 aluminium alloy. In particular, measurements were made of the phase shift between axial strain and transverse strain. To describe this phenomenon the term "Poisson factor" has been adopted, where the magnitude of the Poisson factor is the sine of the phase angle between the strains, assuming harmonic variations. The aluminium alloy was chosen because it is a common low loss material used as a reference in damping experiments. It has been found that, unlike damping, the Poisson factor of this material has a significant amplitude, is frequency dependent and is negative: i.e., the transverse strain leads the axial strain even at relatively low frequencies. © 1992.