Investigations into the clamping effect of monomaterial dowel connections by means of mechanical anchoring

In the field of wood-to-wood connections with round wooden dowels, complex procedures are usually required to mechanically secure the position in the drilled hole without using glue. Possibilities range from friction welding to drying the dowel before insertion. Therefore, a new approach should be investigated: mechanical anchoring by expanding the cross section with a wooden nail on the face side.

In order to determine effective joints, variant tests were first carried out with differently processed dowels in laminated veneer panels, resulting in a test series of 80 specimens. The drilling and anchoring of the dowels was fully automated using an industrial robot. The bond achieved for each variation was examined in pull-out tests. The aim was to achieve load-bearing joints under economical production conditions.

The use of nails resulted in better mechanical anchoring (in terms of friction in N/mm²) than the pull-out tests found in the literature for welded or hygroscopically expanded dowels. The joint is therefore very suitable for single material construction.

Niels Clasen

Keywords: Wood connections, clamping effect, wooden dowels, pull-out strength, monomaterial