PREDICTION OF ELASTIC CONSTANTS AND THERMAL EXPANSION
Table 5.5 How Codes Model Quasi-Laminar Plates
Code Summary of Method
µTex-10
µTex-20
Full thickness FEM calculation
Traction free surfaces included in boundary conditions
A, B, and D matrices computed for full thickness
TEXCAD 3D stiffness matrix computed for single layer
A, B, and D matrices calculated by standard laminate theory
Plane stress assumed
PW
SAT5
SAT8
A, B, and D matrices computed for a single layer
Stack of layers not treated (subsequent laminate analysis required)
SAWC 3D stiffness matrix computed for single layer
Macro elements can be used to make stacked laminate
Surface boundary layer effects handled by FE solution.
CCM-TEX 3D stiffness matrix computed for whole thickness
WEAVE Plate treated as homogeneous, orthotropic body
Layer dimensions used to compute flexural rigidity only.
BINMOD Full thickness FEM calculation
Boundary conditions, including traction-free surfaces, defined by
user.
If the 3D compliance tensor,
, of a composite is available from one of the codes,
then the A matrix for a plate in which plane stress conditions prevail can be computed as
follows:
A h
S S S
S S S
S S S
/ =
−
1111 1122 1112
1122 2222 2212
1112 2212 1212
1
(5.31)
where h is the plate thickness. The codes PW, SAT5, and SAT8 assume plane stress
conditions to evaluate the properties of individual plies.
Thus the codes TEXCAD, PW, SAT5, SAT8, µTEX-10, and µTEX-20 can all
be used to predict plate properties.
Nonlaminar, Nonperiodic Textile Composites
For nonlaminar, nonperiodic composites, neither plane stress conditions nor unit
cells should be part of the modeling approach. A more general method is required. To
date, the only candidate is the Binary Model (implemented in code BINMOD), whose
treatment of geometry has already been described (see above). Stiffness matrices are
computed in the Binary Model by simulating some representative volume element (not a
