Evaluation of the transverse strength of reed stalks

Common reed (Phragmites australis) is a grass which has spread nearly all over the globe. It is common in many kinds of wet habitats. Common reed is a very tall grass, reaching at best the height of four meters on the coasts of the Baltic Sea. In the wintertime the straw becomes a hard, yellowish stem, which makes it possible to exploit the reed also in construction. Reed material has been exploited in many ways around the Baltic Sea for centuries. In construction, reed has been used for roof materials and heat insulation. People are increasingly focusing on sustainable development and the use of natural materials instead of plastics. The reed stem is like a natural pipe. It is already used in the production of cocktail straws. However, there is a much wider range of uses, such as toy components etc. Such applications require that the reed stem is not flattened after cutting. Likewise, the end of the stem must be free of sharp edges and smooth. In previous studies, non-destructive cutting of reeds using abrasive discs was evaluated. In order to create a device for non-destructive cutting of reeds, it is necessary to know the allowable strength of the reed stalk. This paper analyses the reed straw fastening device and evaluates the transverse strength of reed stalks of different diameters. The tests were performed on reeds with a diameter of 6 to 10 mm. The developed reed straw gripping mechanism ensures non-destructive fixing of the straw during reed cutting, if the compressive force generated by the elastic clamps does not exceed the transverse compressive strength of the straw. The highest strength was found for reeds with a diameter of 9 mm, it reached 56.14 N. As the stem diameter increased to 10 mm, the compressive strength decreased slightly to 54.2 N.