Flexible document model and related simulation method

A computer-implemented method of simulating a mechanized flexible document transport process in at least one flexible document transport machine, wherein the computer-implemented method is based on a computer-implemented model of a flexible document, wherein the flexible document is in the shape of a parallelepiped, wherein the flexible document is decomposed into one or more layers, wherein each layer of said one or more layers comprises a plurality of rigid bodies shaped as a parallelepiped, wherein each rigid body has a longitudinal axis, a transverse axis orthogonal to the longitudinal axis, and a thickness axis orthogonal to both the longitudinal axis and the transverse axis, wherein each rigid body is connected to all rigid bodies that are adjacent to it along both its longitudinal axis and its transverse axis by means of a plurality of connecting elements connected to connection edges of adjacent rigid bodies, wherein the connecting edges of each rigid body are parallel to the thickness axis, wherein each connecting edge of each connected rigid body is connected to a connecting edge of a rigid body adjacent to it by means of

• a first connection spring having a rotational stiffness about a rotation axis that is orthogonal to the thickness axis of said connected rigid body and to the axis along which the connected rigid body is connected to the adjacent rigid body,
• and wherein each connecting edge of each connected rigid body is also connected to a connecting edge of a rigid body adjacent to it by a connecting structure selected from the group comprising or consisting of
• a set of further three connection springs consisting of a second connection spring having a translational stiffness along the longitudinal axis of said connected rigid body, a third connection spring having a translational stiffness along the transverse axis of said connected rigid body, and a fourth connection spring having a translational stiffness along the thickness axis of said connected rigid body, and
• a connecting ball joint,
• wherein at least one element of said at least one flexible document transport machine is modeled as a rigid body, the computer-implemented method comprising:
• a first phase of detecting a contact between the flexible document and said at least one element of the flexible document transport machine, and
• a second phase of calculation of contact forces,
• wherein contact between the flexible document and said at least one element of the flexible document transport machine is recognized when a distance between the flexible document and said at least one element of the flexible document transport machine is less than zero, wherein said distance is defined as the penetration depth.