We show that flexural waves can be focused in a beam to an extent that induces precisely controlled dynamic fracture of the beam. Flexural waves are excited at one end of a finite beam and focus at another location along the beam to form a shorter but much larger bending-moment pulse. The strong focusing is achieved by use of the frequency dependence of the phase and group velocity of flexural waves, as well as the superposition of multiple reflections. Amplification of the actuator input by a factor of 20 is achieved solely by wave focusing, proving the potential of such a technique.

• Received 12 October 2017
• Revised 24 May 2018

DOI:https://doi.org/10.1103/PhysRevApplied.10.044021

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society