New universality class for the fragmentation of plastic materials

Area of Science:

• Materials Science
• Physics
• Polymer Science

Background:

• Polymeric materials exhibit complex fragmentation behaviors under impact.
• Existing models for bulk material fragmentation do not fully capture polymer-specific responses.

Purpose of the Study:

• To experimentally and theoretically investigate the fragmentation of polypropylene particles upon impact.
• To identify the underlying mechanisms governing polymer fragmentation and fragment size distribution.
• To establish a new universality class for polymer fragmentation phenomena.

Main Methods:

• Experimental impact tests of spherical polypropylene particles against a hard surface.
• Development and application of a 3D discrete element model (DEM).
• Analysis of fragment mass distribution and material deformation.

Main Results:

• Observed a power law mass distribution of fragments with an exponent of approximately 1.2.
• The experimentally determined exponent differs significantly from those of 3D bulk materials.
• The 3D DEM accurately reproduced large permanent deformations and the novel mass distribution exponent.

Conclusions:

• Shear dominance in crack formation is critical for polymer fragmentation.
• The plastic response of the polymer material leads to a unique fragmentation universality class.
• This research provides new insights into the physics of polymer fragmentation.