Dynamic test method for full body harnesses exploited in cold climates

Issues of ensuring the safety of working on height do not lose their relevance. Civil engineering is in the first place of the amount of injuries and deaths. It accounts for 17% of the structure of the main types of economy activity. The main reason of injuries is the fall from a height (30.5% of all injuries) More than 40% of accidents are lethal or cause partly or complete inability to work. The paper considers safety during ascent and descent on caged ladders, representing a way of collective protection. The construction of vertical ladders, arc cages and the mechanic of worker ascent are considered. Preliminary kinematic model of human fall has been considered during tests, using falling mannequin on caged ladders, with additional safety systems and without them. The analysis show, that caged ladders cannot provide enough protection and create an imaginary protection threat especially when the construction has three vertical bars, which has been set and tested. There is a high probability of falling on the ground or another platform. The paper shows, that cages are not as safe as personal protection equipment, installed on ladders. Some normative documents about vertical ladders allow falling from height less than 10m, which raises many questions about the safety of using that standards.

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Determination of the Parachute Harness Critical Load Based on Load Distribution into Individual Straps with Respect of the Skydiver’s Body Position

Grim

Popela

Jebáček

et al. 2023

Aerospace

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This article evaluates the redistribution of forces to the parachute harness during an opening shock load and also defines the ultimate limit load of the personal parachute harness by specifying the weakest construction element and its load capacity. The primary goal of this research was not only to detect the critical elements but also to gain an understanding of the force redistribution at various load levels, which could represent changes in body mass or aerodynamic properties of the parachute during the opening phase. To capture all the phenomena of the parachutist’s body deceleration, this study also includes loading the body out of the steady descending position and asymmetrical cases. Thus, the result represents not only idealized loading but also realistic limit cases, such as asymmetric canopy inflation or system activation when the skydiver is in a non-standard position. The results revealed a significant difference in the strength utilization of the individual components. Specifically, the back webbing was found to carry a fractional load compared to the other webbing used in the design in most of the scenarios tested. Reaching the maximum allowable strength was first achieved in the asymmetric load test case, where the total force would be equal to the value of 7.963 kN, which corresponds to the maximum permissible strength of the carabiner on the measuring element three. In the same test case, the second weakest point would reach the limiting load force when the entire harness is loaded with 67.89 kN. This information and the subsequent analysis of the individual nodes provide a great opportunity for further strength and weight optimization of the design, without reducing the load capacity of the harness as a system. The findings of this study will be used for further testing and possible harness robustness optimization for both military and sport parachuting.

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Dynamic test method for full body harnesses exploited in cold climates

Cited by 4 publications

References 11 publications

Correction of the Test Method for Ladders with Removable Steps

Correction of the Test Method for Ladders with Removable Steps

Safety cages efficiency during ascent and descent on vertical ladders

Determination of the Parachute Harness Critical Load Based on Load Distribution into Individual Straps with Respect of the Skydiver’s Body Position

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