ENGLISH
Instruction Manual
4
MEASURING OF THE BENDING FRACTURE STRENGTH
The Fractometer II puts bending load on the core sample that was
taken from a wooden structure until it breaks. The bending break moment,
the breaking angle and the fracture energy can be determined.
Picture 1
FIBRE DIRECTION
To determine the radial bending strength it is important that the fibre
direction of the core sample is positioned parallel to the applied force.
Fibre direction
Used force
Core sample
BENDING STRENGTH
Due to the bending of the trunk, tension is transmitted in axial direction
to the trunk. In roots and curved trunks we will see perpendicular stress
or radial tensions. The radial tension strength is the resistance, which the
trunk opposes to a failure by perpendicular stress. This firmness works
against the emergence of the misfortune beam break.
PROCEDURE
The determination of the radial bending strength takes place in the
clamping device at the bending lever (Abb. 1).
The core sample is clamped in
Fibre Direction
into the device.
Then it is broken into several 11 mm long sample pieces to determine
the maximum strength or the radial bending strength. With the 11 mm
sample both measurements are possible.
Detail:
Insertion of core sample
for measurement of
bending fracture strength
Detail
Radial Bending Strength
