A COMPLETE MATERIAL LAW OF PAPER FOR MODELLING AND SIMULATION OF FINISHING PROCESSES

摘要

A complete three-dimensional material law is necessary for the mathematical description of the material behaviour and for the simulation and calculation of finishing or converting processes. In order to achieve this goal, all necessary material properties have been experimentally determined for different paper and cardboard grades. New testing equipments and analysis methods have been developed to record the complete force-displacement-relations in all main directions (MD, CD, ZD) and for every possible axial and shear loading condition. Based on experiments a complete three dimensional nonlinear material law is developed, which is able to describe mathematically the complete mechanical behaviour of paper from the macroscopic point of view. This new material law contains an excellent plastification model and stiffening effects. The described material law is implemented into the FEM-System Marc&Mentat, which now allows the simulation and calculation of paper stress-strain-behaviour in finishing and converting processes. The implementation of the new material law achieves a very good correlation between simulations and experiments.