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Regular version of the site

Article

Alternating shear orientation during cyclic loading facilitates yielding in amorphous materials

Journal of Materials Engineering and Performance. 2020. Vol. 29. P. 7328-7335.

The influence of alternating shear orientation and strain amplitude
of cyclic loading on yielding in amorphous solids is investigated
using molecular dynamics simulations. The model glass is represented
via a binary mixture that was rapidly cooled well below the glass
transition temperature and then subjected to oscillatory shear
deformation. It was shown that periodic loading at strain amplitudes
above the critical value first induces structural relaxation via
irreversible displacements of clusters of atoms during a number of
transient cycles, followed by an increase in potential energy due to
the formation of a system-spanning shear band. Upon approaching the
critical strain amplitude from above, the number of transient cycles
required to reach the yielding transition increases. Interestingly,
it was found that when the shear orientation is periodically
alternated in two or three dimensions, the number of transient
cycles is reduced but the critical strain amplitude remains the same
as in the case of periodic shear along a single plane. After the
yielding transition, the material outside the shear band continues
strain-induced relaxation, except when the shear orientation is
alternated in three dimensions and the glass is deformed along the
shear band with the imposed strain amplitude every third cycle.