NUMERICAL-CALCULATION OF STRESSES AND STR AIN AND HARDNESS OF PAPER ROLLS

Based on numerical methods stresses and strains in paper rolls are cal culated taking the nonlinear stress-strain behaviour of paper into acc ount. The roll hardness across reel diameter can be estimated, because the paper compression is not neglected, Roll hardness is defined as t he apparent density of paper in the roll under radial compression. For the calculation the grammage is divided by the individual caliper of each wound layer affected by compression in z-direction.