This is a plane-strain model in Abaqus/Explicit. The material model is elastic/plastic with continuum damage. It also has a Us-Up equation of state property with tensile failure.  A pressure pulse sends a pressure wave through the material. It is reflected as a negative pressure wave which causes the void. The video was created in Abaqus/CAE which allows the animation of a contour plot that has its legend recomputed for each frame.