Effect of friction on cut resistance of polymers

It is generally recognized that resistance to cutting consists of two aspects, one reflecting the intrinsic strength of the material, and the other a frictional contribution. In practice, cutting usually involves a normal force and a sliding movement. This work aims to analyze the effects of friction on cutting resistance of materials in the presence of a normal force and sliding movement of a sharp object. International Standard ISO 13997 is used as a reference to evaluate the cut resistance of some selected protective materials under practical conditions in service. The resistance to cutting of a material in the presence of both a normal force and sliding movement of a sharp object is strongly controlled by friction between the blade and the cut material. An increase in the friction coefficient can enhance or reduce the cut resistance, depending on the thickness, and the microstructure of the material to be cut. Thus the total energy required to propagate a cut strongly depends on the friction coefficient and consists of two components: The lost energy dissipated by the squeezing force exerted by the cut material, due to its elasticity, on the blade sides, and the essential cutting energy at the edge of the blade. These energies have opposite effects on the cutting resistance of materials. An increase in the energy dissipated in gripping frictional force increases the cut resistance, whereas an increase in friction at the blade's edge reduces the energy required to cut the material.