ANALYTICAL METHODS FOR TEXTILE COMPOSITES
8-20
to account for transverse stiffness at yarn crossing points. Waviness can be
accounted for by randomly offsetting nodes in the model according to a specified
normal distribution.
Model:
The binary model prints the stresses and strains for the effective medium elements
and tow elements. The code is designed to handle nonlinear behavior. With these
capabilities, it should be ideal for studying progressive failure. Indeed, it is the only
code available that should be able to model events at large strains, where mechanical
lockup between yarns starts to occur. However, use of the code for progressive
failure is not currently documented.
Required:
- Mesh data for effective medium elements (element size and mesh density), grid
data for line elements. Automatic meshing assigns line elements to nodes based on a
regular pattern defined by first position, last position, and increment.
- Axial stiffness of yarns and stiffness of effective medium elements
(documentation describes how to assign latter). Standard deviation in z axis location
of nodes for stuffers and fillers can be entered, which the code uses to assign
random z offsets. Loading conditions are prescribed strains or forces applied to
specific planes.
Output:
Iteration summary, total forces acting on loaded plane, stress and strain at each
element quadrature point.
Large database of elastic properties for several weaves provided in references.
Failure data and observed failure progression are also documented.
Comments:
Given the difficulties of making 3D finite element models of plain weaves, the
binary model makes a reasonable compromise between geometric fidelity and
practicality. The simplification of the geometry allows representation of complex
