Introduction: The article is focused on description and comparison of the selected friction knots manners during static load.
Aim of Study: The main objectives of the study are to find the proper values and standard manners of five friction knots used in military climbing, rescue techniques, arboriculture and mountaineering. How strong is the system constructed from friction knot tied from reep cord and low stretch kernmantle rope? What are the processes happening in the friction system leading to its malfunction and where the breakage happens? These were the unanswered questions we were facing to.
Material and Methods: Experimental research was conducted on five selected friction knots – Blake hitch (ABoK #1693), Double prusik (variant of ABoK #1763), Triple prusik (ABoK #1763), Distel hitch (ABoK #1465) and Vánočka knot (ABoK #1758). All of them were part of friction system which was tested 10 times in laboratory conditions on certified device. Firstly, nominal static strength of used material was tested. The initial phase was followed by testing all of the selected friction systems and statistical analysis of all attempts and their comparison between each other. The oneway ANOVA and multi-comparative Tukey test in post hoc analysis were used.
Results: The nominal strength of used material is stronger than ordered by European norms. 81 % of friction system malfunctions happen in friction knot. All selected friction knots decrease the nominal strength of friction systems. The range of decrease differs between 14 % and 49 % depending on specific friction knot and its maximal nominal strength. Number of strands used for knot tying is not determining parameter of its maximal nominal strength.
Conclusion: The friction knots are commonly used in many expert fields of human activities. Their proper selection based on our results might be crucial for safety as well as using the features specific friction knots have.