Page 9 - Shimadzu Journal vol.2 Issue3

New Material

Additional measurements - With the aim of a more detailed
characterization of vulcanized fiber, further measurements have
been used in the investigations. To exclude the damaging
influence of the extensometer knifes a video extensometer
(Shimadzu, Type TRViewX) has been used to measure the strain
during the tests. Therefore reference marks have been attached to
the specimen surface (Fig. 9). The results in strain measurement
confirmed the measurements taken with the tactile extensometer.

Fig. 11 Experimental set up with high-speed camera system

With a recording frequency of 500,000 frames per second, the
time from crack formation to failure of the specimen could be
determined with 3 x 10 seconds (Fig. 12).
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Fig. 9 Experimental set up with video extensometer

Further information about the material behavior was provided by
thermometric measurements and infrared thermography. At the
beginning of the test in the area of elastic deformation, the flat
vulcanized fiber specimen absorbed energy in the form of heat
which leads to a decrease in temperature. At the transition
between the elastic and the elastic-plastic area, the temperature Fig. 12 Crack formation and propagation behavior in tensile test
increased till the fracture of the specimen (Fig. 10).

3. Conclusions
For the characterization of technical vulcanized fiber with
different load and climate profiles additional to conventional
stress-strain-measurement, a video extensometer, a thermography
system and a high-speed camera were used. Deformation speed
and relative humidity have a significant influence on the
quasistatic material properties. An increase in relative humidity
leads to an increase in maximum strain and a decrease in
E-modulus and the tensile strength. With an increasing
deformation speed E-modulus increased too, but tensile strength
and maximum strain showed a maximum value in the middle
region. The use of additional measurement systems was well
suitable for the detailed characterization of the deformation
behavior of vulcanized fiber.

4. Outlook
This article provides quasistatic values of technical vulcanized
fiber. The scope of a following article is the characterization of the
fatigue behavior. On the basis of quasistatic and cyclic material
values it is possible to optimize the process- and product-oriented
material properties. This leads to various new fields of application.

Fig. 10 Thermal images of different tensile test stages
5. Extended Abstract of:
Penning, B.; Walther, F.; Dumke, D.; Künne, B.: Einfluss der
Additionally the crack formation and the crack growth were Verformungsgeschwindigkeit und des Feuchtegehaltes auf das
analyzed. Thermography (Infra-Tec, Type IR8800) provided a quasistatische Verformungsverhalten technischer Vulkanfiber. MP
reliable indicator of the starting point of cracks. A high-speed Materials Testing 55, 4 (2013) 276-284.
camera (Shimadzu, Type Hyper Vision II) was used for the
investigation of the crack propagation (Fig. 11). http://www.wpt-info.de

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