Nonlinear dynamic behavior of parachute static lines

Abrate, Serge; Dooley, Robert B.; Kaste, Robert; Thibault, Gary; Millette, William

doi:10.1016/s0263-8223(03)00025-4

Cited by 9 publications

(4 citation statements)

References 1 publication

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“…the leeward lines of a moored device). The eect of snatch loading on synthetic materials has been well studied for other applications (including parachute cords [86], aircraft arresting systems [87] and recreational uses such as climbing and sailing [88]) and Nylon 6 Table 3: Indicative durability of synthetic materials which could potentially be used for MRE mooring systems. The classications; good, average and poor are taken from Refs.…”

Section: Degradation Mechanismsmentioning

confidence: 99%

Synthetic mooring ropes for marine renewable energy applications

et al. 2015

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Synthetic mooring ropes have a proven track record of use in harsh operating conditions over the past two decades. As one of the main users of ropes for permanent mooring systems, the oil and gas industry has opted for these components because they possess performance characteristics and economies of scale which are in many respects superior to steel components. Given this accrued experience, it is unsurprising that several marine renewable energy (MRE) device developers have utilised synthetic ropes, motivated by the need to specify economical, reliable and durable mooring systems. Whilst these components are potentially an enabling technology for the MRE sector, this is a new eld of application which can feature highly dynamic mooring tensions and consequently existing certication practices may not be directly applicable. Based on the expertise of the authors, this paper provides a state-of-the-art overview of synthetic ropes in the context of MRE mooring systems, including key information about aspects of specication (performance attributes, classication and testing) as well as application (installation, degradation, maintenance, inspection and decommissioning). It is the intention of this review to provide valuable insight for device developers who are considering using ropes in the specication of t for purpose mooring systems.

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Section: Degradation Mechanismsmentioning

confidence: 99%

Synthetic mooring ropes for marine renewable energy applications

et al. 2015

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“…Snap loads in static lines involved in parachute deployment by the military were obtained experimentally by Abrate et al [1] and Millette et al [25] using drop tests at the US Army Soldier Systems Center in Natick, Massachusetts. Two types of these nylon-webbing restraint straps were tested dynamically, Absorb-Edge and MIL-W-4088 Type VIII.…”

Section: Drop Heightmentioning

confidence: 99%

Experimental Snap Loading of Synthetic Ropes

Hennessey

Pearson

Plaut

2004

Shock and Vibration

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Large tensile forces, known as snap loads, can occur when a slack rope becomes taut. Such forces may damage the rope or masses connected to it. Experiments are described in which one end of a rope is attached to the top of a drop tower and the bottom end is attached to a weight. The weight is raised to a certain height and then released. The force at the top of the rope and the acceleration of the weight are recorded during the first snap load that occurs. Repeated drop tests are performed on each rope. The effects of the type of rope, drop height, drop weight, whether the rope has been subjected to static precycling, and the number of previous dynamic tests are examined. A mathematical model is proposed for the rope force as a function of the displacement and velocity of the weight.

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“…In many applications, elastic deformation of dynamic ropes and/or secondary energy absorbers are employed to reduce the arresting load transferred to the user to reduce the risk & Gavin P. Horn ghorn@illinois.edu of injury from dynamic loading. A great deal of research has been conducted to characterize the quasistatic and dynamic strength and energy absorption characteristics of ropes used in the maritime industry [4][5][6][7][8], industrial fall protection [9,10], recreational sport climbing [11][12][13][14] and even in single polymer strands [15,16]. Secondary components (that remove energy from the system through controlled failure, friction, or deformation as they are loaded) have been shown to reduce the impact load on the individual to a safer range [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Knots to Reduce the Maximum Dynamic Arresting Load in Rope Systems

Martin

Boron

Obstalecki³

et al. 2015

J. dynamic behavior mater.

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Impact loads to the human body due to falls from height can be mitigated by well-designed and characterized fall protection systems. While energy absorption methods using rope deformation and/or accessory components have previously been evaluated, the ability for simple knots tied in the system to alter impact loads has not been studied in detail. We quantify the effectiveness of various common knots to reduce dynamic loads in typical fall scenarios for which the systems are designed, and interpret this change in the context of rope strength reduction due to the knot. Knots are shown to significantly (45-60 %) reduce the quasistatic strength of rope when compared to a manufactured sewn-eye (40 %). A single exception to this outcome is with the quadruple overhand on a bite (30-35 %). Knots significantly reduce the maximum arresting load due to a dynamic impact event when compared to ropes without knots, providing significantly more energy absorption than the sewn-eye alone. In nearly all rope/knot combinations, the ratio of maximum arrest load (MAL) to breaking strength was lower with the knotted ropes when compared to the sewn-eye terminations. In particular, the quadruple overhand on a bite tied in the Technora-Technora rope resulted in MALs that were only 33 % of the minimum breaking strength (MBS). Ropes with sewn-eye terminations resulted in MALs that were 80 % of the MBS. From the scenarios investigated, the quadruple overhand on a bite provides a favorable reduction in arrest loads with the smallest associated loss of strength.

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Nonlinear dynamic behavior of parachute static lines

Cited by 9 publications

References 1 publication

Synthetic mooring ropes for marine renewable energy applications

Synthetic mooring ropes for marine renewable energy applications

Experimental Snap Loading of Synthetic Ropes

Feasibility of Knots to Reduce the Maximum Dynamic Arresting Load in Rope Systems

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