*2.2. Method for Determining Contact Parameters*

The contact parameters of the ramie stalk discrete element simulation model included the coefficient of restitution, coefficient of static friction, coefficient of rolling friction between the phloem and phloem, phloem and Q235A steel, phloem and xylem, xylem and xylem, and xylem and Q235A steel. Among them, the physical tests mainly measured the contact parameters between the phloem and Q235A steel, phloem and xylem, and xylem and Q235A steel. As the phloem–phloem and xylem–xylem contact parameters are difficult to obtain directly from physical tests, physical tests of the stacking angle of phloem and xylem needed to be carried out and calibrated by subsequent simulation tests of the stacking angle.
