The composition of skis is very complex. The skis have to provide certain properties of which rigidity, strength and weight are the most important. All of these properties mostly come from the inner core of the skis. To produce high-quality skis, wood is usually used for the core, along with some other alternatives: carbon fibres, titanium reinforcements, etc. Apart from that, the natural fibre composites are increasingly coming to the forefront. Hemp, the oldest field crop, has long and very strong fibres, located along the whole length of the stem. They present a great alternative to other artificial fibres currently used to form light composites. To make the board, we used long hemp fibres as the basic material, and melamine urea formaldehyde glue as a binder. We then exposed the produced boards to the cyclic load at various percentages of maximum force, determined beforehand by performing a bending test on the industrially manufactured board made from short hemp fibres. We have established that there are differences among the deformations in all of the samples. These occur between the initial deformation and the deformation after the 50th cycle depending on the applied force. Larger deformations were found at higher force loads, up to 15 % of permanent deformation. During the cyclic testing, some of the examined items fractured, when exposed to cold conditions (-15 °C) under high force loads. A positive effect of using longer fibres was noticed, since the deformations of the laboratory-made boards were lower than those in the reference boards. We have also found out the differences in material behaviour depending on the environmental conditions the samples were exposed to.
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