Abstract Zero Group Velocity (ZGV) modes are peculiar guided waves that can exist in
elastic plates or cylinders, and have proved to be very sensitive tools in characterizing
materials or thickness variations with sub-percent accuracy at space resolutions of about the
plate thickness. In this article we show theoretically and experimentally how such a mode
can be generated as the sum-frequency interaction of two high amplitude primary waves,
and then serve as a local probe of material non-linearity. The solutions to the phase …