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The influence of surface roughness on the compressive behaviour of paper

The influence of surface roughness on the compressive behaviour of paper was studied in platen press experiments. Handsheets were manufactured from the same pulp with different grammages: 110, 220 and 1050 g/m. As the grammage of the paper increased, the stiffness of the paper in compression increased significantly. The thinner sheets also showed a higher degree of non-linear behaviour. Part of the non-linear behaviour was due to the surface roughness. In order to model the compression properties of paper in the thickness direction, material parameters were derived from the compression experiments with the 1050 g/m2 sheets. The influence of surface roughness on the compressive behaviour of paper was modelled using the thickness profiles measured with a STFI thickness tester and a model consisting of independent springs. The model generally predicted a stiffer behaviour than the behaviour observed in the compression experiments.