Fractometer

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The fractometer is a measuring and testing device for examining the strength of wood in trees, especially for measuring flexural fracture and compressive strength .

Depending on the device version (see below), the fractometer can be used to determine the bending rupture and / or compressive strength parameters of drill cores .

With the help of the incremental drill , meaningful drill core samples can be taken quickly and easily from trees or wooden poles , which are then clamped into the corresponding device of the fractometer for measurement. This enables objective statements to be made about the flexural strength and compressive strength of the wood . It is very important to take the core from the right places in the tree. Non-reflective drilling core removals only damage the tree unnecessarily.

The measurement should take place immediately after the drill core has been removed, otherwise the wood would dry out and the measured values ​​would be falsified. During the measurement itself, it must be ensured that the wood fibers are arranged parallel to the surface of the fractometer. The measurement should not take longer than a minute. Otherwise the result-falsifying creep effect occurs.

The measurement results of healthy wood are species-specific and there are tables in which these values ​​are listed. However, these are only mean values, deviations upwards and downwards are quite possible without immediately having to conclude that the tree is infected with rot. The different measured values ​​are sometimes due to the wind exposure or the oblique growth of the trees. Rot causes greatly reduced material properties and can be easily recognized with a fractometer.

The corresponding fractometer table enables quick determinations and a comparison of the wood quality in order to assess the stability and wood properties of a tree. The table values ​​are only guidelines, however, as the tree must always be viewed as a whole.

Individual evidence

1. ^ Deutsche Welle (www.dw.com): The body language of trees | DW | 09/08/2014. Retrieved on February 28, 2019 (German). 
2. ↑ http://www.deritec.de/DE/052.html