Non-destructive diagnostics of uniformity of loading of the sheet of paper

Abstract

To ensure high quality of printing the paper in the printing machine is to experience uniform loading: the stresses are to be uniformly distributed across the width of the paper. For the diagnostics of the uniformity of loading the use of time averaged moiré analysis of transverse vibrations of the paper is proposed.
Orthotropic constitutive model is to be taken into account for machine made paper, while laboratory made sheets are usually isotropic. It is assumed that a paper in a printing device is loaded in its plane and thus a problem of plane stress is analyzed. Principal stresses are calculated and represented at the centers of finite elements. They substantially determine the vibration behavior and stability of the paper.