Agriculture Reference
In-Depth Information
X
min
X
max
K1 / GADO
Median
Mean
n = 50
Instron / 3,2 mm
2 mm/ min
Pressley / Plexig.
K1 / FA
K1 / GA
K1 / RS
Fineness related strength in cN/tex
based on single element test
Fig. 10.21.
Fineness-related strength measured with the Instron universal tensile-tester by testing single
elements (Müssig, 2001a).
Table 10.9.
Dia-Stron values of the tested hemp (single-element test).
Corrected
break strain
(%)
Cross-
sectional
area (
μ
m
2
)
Gravimetric
fineness*
(tex)
Young's
modulus
(N/mm
2
)
Fibre/tested
elements
Break load
(N)
Strength
(N/mm
2
)
Strength
(cN/tex)*
K1/GA
Mean
7.6
7.7
13,299
19.9
735.0
49.0
11,481
82
Median
7.1
6.6
11,565
17.3
627.0
41.8
8,202
K1/MA
Mean
6.5
6.7
13,044
19.6
672.0
44.8
11,345
78
Median
6.5
6.0
10,036
15.0
572.6
38.2
9,539
K1/FA
Mean
7.8
8.6
15,927
23.9
611.7
40.8
9,013
88
Median
8.0
8.0
14,786
22.2
561.0
37.4
7,812
K1/GAD
Mean
4.5
1.7
3,318
5.0
666.8
44.5
15,989
80
Median
4.2
1.3
2,343
3.5
596.2
39.8
13,470
K1/GADO
Mean
5.0
1.9
3,863
5.8
696.9
46.5
14,968
73
Median
4.9
1.6
2,810
4.2
446.4
37.6
11,440
The collective test is the first choice for a
quality check to compare the strength of hemp
with a comparable fibre bundle fineness.
Because of the small number of necessary
tests, this method is very suitable for produc-
tion quality control, for example in a mechani-
cal separation plant, or, as described by Dreyer
et al
. (2002), to compare hemp produced in
an enzymatic separation process.
To get physically precise data, for exam-
ple for a numerical simulation of the behaviour
of a natural fibre reinforced plastic, it is neces-
sary to use the single-element test. With the
Dia-Stron system, it is possible to get area-
related strength and Young's modulus values.
Using this method, new knowledge can be
generated regarding the mechanical properties
of fibres.
10.5
Conclusion and Outlook
From the results presented here, it is obvious
that even the process of harvesting has signifi-
cant influence on fibre quality. Processing
freshly harvested stems causes greater damage
than processing dried stems. Subsequent card-
ing of damaged fibres causes enhanced loss of
material due to the higher number of short
fibre bundles.
The measurements necessary for quality
control can be undertaken easily by using the
