E. Andreassen et al., EFFECTS OF THE DISTRIBUTIONS OF POLYPROPYLENE FIBER PROPERTIES ON THETENSILE RESPONSE OF FIBER ASSEMBLIES, Polymer, 36(6), 1995, pp. 1189-1198
The tensile response of some simple fibre assemblies is calculated, us
ing the actual stress-strain relationships of constituent fibres. Thes
e stress-strain relationships are obtained by a scaling procedure, wit
h distributions of ultimate tensile properties and an average stress-s
train curve as input. Two polypropylene fibres with different polydisp
ersity index, but the same weight-average molecular weight and draw ra
tio, are considered in this article. The fibre with the narrowest mole
cular weight distribution (MWD) has about 30% higher average strength.
On the other hand, if bundles with a large number of fibres are compa
red, the strength of a bundle consisting of fibres with narrow MWD is
less than 10% higher. The maximum strength of a random planar distribu
tion of fibres is 36% and 44% of the average fibre strength, for fibre
s with narrow and broad MWD, respectively. The strength of a chain-of-
bundles decreases as the number of bundles increases, and as the numbe
r of fibres in each bundle decreases. When the number of bundles is la
rge, the strength of a chain-of-bundles containing fibres with broad M
WD exceeds that of a chain containing fibres with narrow MWD. The asse
mblies considered in this article illustrate effects in real assemblie
s, such as non-woven fabrics. They also provide references for the ten
sile properties of real assemblies.