Needle-Punching process is a mechanical
method by which entanglement of fibrous webs can be
enhanced. Fiber entanglement together with fabric weight
can be held responsible for the variations in the mechanical
properties of nonwovens. In this work, mean fiber orientation
angle and fabric weight measurements were used for
prediction of bending and tensile properties of needlepunched fabrics. Samples of needled nonwoven fabrics in
four groups with different fabric weights were produced
using appropriate carding/cross-lapping machines. The
samples of each weight group were needled at various punch
densities and needle penetration depths. The orientation of
the fibers in the samples was determined using Radon
transform method. Bending stiffness and breaking strength of
the samples in both machine-direction and cross-machine
direction were determined using two simply supported beam
system and strip method, respectively. The results indicated
that an increase in the amount of punch-density generally
leads to variation in orientation angle of the fibers in the
samples. It was observed that an increase in the amount of
punch-density led to an increase in mean fiber orientation
angle in all samples along the machine-direction. This is due
to the displacement of the fibers by the needling process.
Additionally, fiber orientation pattern of the samples
enormously changed due to the changes in needle penetration
depth. Multiple regressions based on least square method
were used to estimate the mechanical properties of needlepunched fabrics. The results pointed to the paramount
importance of the degree of fiber orientation and fabric
weight as two influential factors controlling the mechanical
properties of needle punched fabrics.