In the image below is the default settings for Erosion Controls under Analysis Settings for Explicit Dynamics.

If you want to see your part “break” then you must set the Geometric Strain Limit to the value of strain that corresponds to the Ulitmate Tensile Stress by dividing by Young’s Modulus or set it to the material property Elongation if you know that value.  The default setting of 1.5 is understood to be 150% strain and that is too large.

Or you could change the erosion to be On Material Failure and add a Failure model to the material in Engineering Data.