Developments in Ceramic Materials Research

Modeling of Thermal Transport in Ceramics Matrix Composites 197
The key to capturing the crimp form in the 8 harness satin weave has been the ‘loft’ part
modelling tool in ABAQUS/CAE which allows the accurate generation of the changing crosssection,
especially at the interlacement points where the warp tows pinch the fill carbon tows
and vice versa. A minimal gap is left between these two crossing tows to model the Carbon
matrix by ‘inserting cell’ as seen present there in Figure 20(b).
Ideally the fibre bundles are considering having a lenticular cross-section shape shown in
Figure 23(a). On one hand these bundles are seen compressed at the tow crossover locations
and then these same tows join their neighboring tows in the same lamina and take up a clearly
rectangular shape after compaction. This transformation from a rectangular area to a
lenticular one and back can only be modeled with ‘lofting’ as explained in Figure 24. ‘Loft’
function in ABAQUS/CAE allows the creation of a 3D object from a pair of 2D sketches and
also with the help of the tracer path, where needed. As an example a lenticular and a
rectangular area are shown in Figure 24(a) and then ‘lofted’ together in Figure 24(b).
‘Extrusion’ function used earlier in the DLR-XT Unit Cell geometry is similarly used here for
generating constant cross-section volumes as seen in Figure 25 model forming straight
sections between the curved sections. The ‘sweep’ function has been used to create the
crossover sections shown as an example in Figure 23. The Unit Cell is shown in Figure 25
without the Carbon matrix enveloping the 8-Harness Satin cloth.
Figure 23. (a) The lenticular area, used for the ‘sweep’ and ‘loft’ function for creating volumes, (b)
same sketch used to form the crossover in the weave between warp and fill tows.
Figure 24. Using Loft function (a) between two surfaces, creating (b) final volume.