Figure 1

Experimental arrangement.Reuse & Permissions

Figure 2

(a): Shadowgraph of the fracture surface in glass indicating the line of interaction between the crack propagating from left and right ($f=5\mathrm{M}\mathrm{H}\mathrm{z}$, $v=480\mathrm{m}\mathrm{/}\mathrm{s}$) and the shear wave propagating in the $\pm z$ direction. Parallel lines, such as the one emphasized by the dashed white line, that appear to be translated along the direction of crack propagation are either arrest lines or undulations of the $x\mathrm{\text{−}}z$ plane about the $z$ axis. The continuous line that begins at the top left part of the figure at the point marked $A$ and reflects at the plate faces at $B$, $C$, represents the interaction between the shear wave and the crack front. (b): Topographic image measured using an interferometric microscope.Reuse & Permissions

Figure 3

Topography of the undulation of the crack surface in the $x$ direction. (a) Variation of the amplitude $A$ of the undulation with respect to the distance $d$ from the transducer ($f=5\mathrm{M}\mathrm{H}\mathrm{z}$ and $v=480\mathrm{m}\mathrm{/}\mathrm{s}$). The straight line slope is $0.1\mathrm{d}\mathrm{B}\mathrm{/}\mathrm{m}\mathrm{m}$. (b): Influence of shear wave frequency $f$ and crack velocity $v$. Plain: $(f=5\mathrm{M}\mathrm{H}\mathrm{z},v=480\mathrm{m}\mathrm{/}\mathrm{s})$; dashed: $(f=5\mathrm{M}\mathrm{H}\mathrm{z},v=867\mathrm{m}\mathrm{/}\mathrm{s})$; dash-dotted: $(f=20\mathrm{M}\mathrm{H}\mathrm{z},v=895\mathrm{m}\mathrm{/}\mathrm{s})$. Data have been shifted vertically for clarity. The corresponding wavelength ${\lambda }_x$ is marked on the figure.Reuse & Permissions

Figure 4

(a): Sketch of the interaction of the shear wave and the crack front at three successive time steps. (b): Schematic diagram of the interaction of shear waves with crack fronts.Reuse & Permissions

Figure 5

Shadowgraph of the fracture surface (a) when the $5\mathrm{M}\mathrm{H}\mathrm{z}$ transducer is placed so that the shear wave propagates in the $y$ direction with a polarization in the $\pm z$ direction and the fracture surface when (b) the perturbation is induced by scribing a groove. The inset shows the variation of the undulation amplitude $A$ with respect to the distance $d$ from the groove. The dotted line represents the limit of measurement resolution, around $10\mathrm{n}\mathrm{m}$.Reuse & Permissions