National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Analysis of dynamic strength of friction knots used in military climbing
Telvák, Radek ; Michalička, Vladimír (advisor) ; Braum, Zdeněk (referee)
Title: Analysis of dynamic strength of friction knots used in military climbing Objectives: The aim of this work is to determine the resulting impact force generated by selected friction systems at different values of the fall factor. To calculate what maximum values of auxiliary Reep cord length and maximum load weight can be achieved without system failure. Determine the correlation between the magnitude of the impact force and the slip length. Methods: This thesis describes an experiment in which the resulting impact force acting on a friction system at different drop factors was determined. A 6mm Reep cord and an 11mm rope and friction knots used in military climbing techniques were selected for analysis. Testing was carried out in a polygon on a drop tower. Each of the friction knots was subjected to 5 tests at the same fall factor. The individual knots were statistically compared with each other in terms of impact force and slip. Using direct proportionality, the maximum possible values of the auxiliary Reep cord length and the weight of the load were determined. A correlation analysis was used to establish a correlation between impact force and slip. Results: It was found that at all measured values of the fall factor, the Twist prusik achieved the lowest values of the resulting impact force...
Static strength analysis of friction knots used in military climbing
Telvák, Radek ; Michalička, Vladimír (advisor) ; Baláš, Jiří (referee)
Title: Analysis of static strength of friction knots used in military climbing. Objectives: Strength determination of selected knots on static ropes under static load. Methods: This bachelor thesis shows a laboratory experiment, where the influence of friction knots on the strength of the Reep cord tied to a static rope under static load was determined. For the purposes, a 6mm Reep cord and 10.5mm rope and friction knots used in military climbing techniques were selected. The experiment was run on a vertical test rig. Each of the selected knots was tested 10 times. Every knot was compared among the others in the first slip, slip length, maximum strength, nominal strength drop and the point of failure. Results: The highest average values of the first slip and the maximum strength were achieved by the Twist prusik. The lowest value of the slip length was measured at the Blake friction knot. Compared to other of the selected knots, the lowest decrease in nominal strength by 14 % was found on the Blake knot, while the highest decrease in nominal strength is found in the Twist prusik. The Reep Cord failed in 81 % of all attempts. Keywords: military climbing, friction knot, knot strength, slip, point of failure, nominal strength

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