Resistograph

The drilling resistance or Resistographie is an examination of trees and woods; thereby creating an electronically controlled devices linearly correlated to the density trace.

Operation

A long, thin needle (shank diameter usually 1.5 and head diameter 3 mm) is drilled into the wood. Measured, recorded, stored and printed, the electric power of the one or both the needle driving motor. With suitable choice of motors and electronic control this power corresponds to the torque on the needle, which in turn corresponds mainly to the mechanical resistance to penetration of the wider needle tip. The measured values ​​obtained in this way correlate with the density of pierced wood ( r ² > 0.9), both in the dry and in green wood. Thus, the measured profiles indicate the course of the apparent density of the wood along the drilling again. The resulting drilling profiles reflect the relative density distribution of the wood.

After appropriate training, including in wood anatomy and biomechanics, predictions can be made about the internal condition of the wood from the measured curves, including over -pressure timber, rot, cavities, cracks and other internal defects as well as the tree-ring growth.

Bohrwiderstandsmessungen means of appropriate measuring devices are carried out by material testing and special operations.

Area of ​​application

The investigation method is used worldwide to tree studies, tree care and control in the context of ensuring public safety, play and Pole Inspection, timber and construction timber investigations. Resistographen come in timber as well as for use in living trees.

Disadvantages

As with all drilling investigation process to the material under investigation is damaged. Moreover, it is in a single measurement at a sample, precise statements require (depending on the wood body ) having a plurality of holes in different places. Thus, a significant damage to the wood body must be taken into account.

Development

The method was developed by Frank Rinn in the 1980s and is protected by trademark law in the 1990s.