Page 7 - Shimadzu Journal vol.2 Issue3

New Material

Influence of Deformation Speed and Humidity on
Quasistatic Deformation Behavior of Vulcanized Fiber
– Experiments with Different Load and Climate Profiles.*

Bastian Peening, Daniel Hülsbusch, Frank Walther, Dominik Dumke and Bernd Künne, Dortmund
*Extended Abstract of paper published in MP Materials Testing in 2013, see bibliography in Chapter 5.

ABSTRACT
The detailed knowledge of the material properties is the basic requirement for design and production engineers, to ensure safe and
efficient operation conditions of structural components. The insufficiently studied construction material vulcanized fiber shall be
investigated microstructure-based and evaluated, regarding the influence of deformation speed and relative humidity on the quasistatic
properties. Besides materialographic and microscopic investigations, an ultra-micro hardness tester was used. The mechanical
characterization was done with an electromechanical universal testing system, a clip-gage and a video extensometer, thermocouples and a
thermography system and a high-speed camera to detect crack formation and propagation.

1. Introduction
In consequence of stagnating research activities only a few
material properties of vulcanized fiber can be found. Technical
vulcanized fiber consists of cotton linters and/or recycled rags. Its
fibers are processed to make absorbent and unsized special
papers, which are joined by a merging process into one
homogenous material by adding a parchmentizing solution. After
bonding, the parchmentizing solution is leached out in a
multistage process by using osmotic forces. Finally, the vulcanized
fiber is dried (Fig. 1). The material properties of technical
vulcanized fiber are comparable to those of engineering plastics, Fig. 2 Experimental set up for tensile tests
but it is fully based on natural resources. This leads to a
A precisely vertical clamping of the specimens with a freely
hygroscopic behavior, which has to be considered in the following
suspended length of 70 mm excluded transverse forces. During the
investigations.
tests strain measurement was performed with an extensometer
(Shimadzu, Type SSG25-50H) with a gage length of 50 mm.
2-2 results
Material - The aim of the production of vulcanized fiber is to
dissolve the layer structure and merge the single fibers. This does
not always succeed as Fig. 3 shows where the layers are
differentiable from each other.
Fig. 1 Continuous production of vulcanized fiber

2. Experimental

2-1 setup and parameters
Specimens used in this investigation with the dimensions 140 mm
x 15 mm were punched out of industrially manufactured
vulcanized fiber with a thickness of 0.8 mm. From the wide field
of influencing variables, deformation speed and relative humidity
were chosen to determine their influence on the mechanical Fig. 3 Light micrograph, transversal cross-section
properties and the quantitative assessment. According to DIN
7738, the deformation speed has to be set to 10 % ± 2.5 % of Scanning electron micrographs show the merging of the fibers in
the freely suspended length in mm/min. Speeds of 1, 5, 10, 100 detail (Fig. 4).
and 1,000 mm/min were used in this investigation. The same DIN
recommends climate conditions with 65 % relative humidity. In
this case 25, 40 and 90 % relative humidity were taken into
account. Therefore the specimens were conditioned in a climate
chamber (Binder, Type KBF 240) at a temperature of 20° C. The
tensile tests were performed directly after taking out the flat
vulcanized fiber specimens of the climate chamber in a universal
testing system (Shimadzu, Type AGS-X) with a maximum load of
5kN (Fig. 2). Fig. 4 Scanning electron micrographs (SEM)

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