Stress field in a web during slitting-opening mode

Abstract

The dynamic stress field in a web during slitting is presented for the opening mode appropriate for razor slitting in the steady state. The integral equations for the general stress and strain fields in a web near a razor blade are solved for the in-plane stress components for a homogeneous, isotropic and linearly elastic web. A wedge-type razor blade profile is used in the analysis. A Coulomb type of friction relation between the shear and normal traction at the interface between the razor and the web is assumed. Analysis is performed to determine the stress components and the contour of effective stress. It is found that the stress distribution in the web can be separated into two parts. One part depends only on the web speed and the other part depends only on the slitter profile. A parametric study is carried out to determine the dependence of the contour of effective stress on the slitter blade profile, the friction coefficient at the web-slitter interface, the web speed during slitting, as well as the web tension. In the parametric study, it is assumed that the web material properties such as Young's modulus, yield strength and fracture toughness are independent of the strain rate or the web speed. The results on the dependence of the contour of effective stress on the slitting parameters reveal that the size of the permanent deformation zone in the slit edge becomes larger when any one of the slitting parameters among the web tension, the razor wedge-angle and the web speed increases while all the other slitting parameters and web material properties are fixed.