scholarly journals Average Force of Deployment and Maximum Arrest Force of Energy Absorbers Lanyards

2020 ◽  
Vol 17 (20) ◽  
pp. 7647
Author(s):  
Elena Ángela Carrión ◽  
Pedro Ignacio Saez ◽  
Juan Carlos Pomares ◽  
Antonio Gonzalez
Keyword(s):  
Empirical Data ◽  
Dynamic Performance ◽  
Free Fall ◽  
Maximum Height ◽  
Time Curve ◽  
Average Force ◽  
Balance Of Forces ◽  
Energy Absorbers ◽  
Fall Arrest ◽  
Energy Absorbing

Energy-absorbing lanyards (EAL) are part of fall arrest systems (FAS), their main mission is to dissipate the energy generated during the fall, ensuring that the arresting force does not cause injury to the user. For the design of FAS as set out in the American standard Z359.6 and the Canadian Z259.16 it is essential to know the deployment force or average arrest force (Fa). Fa is necessary to estimate the elongation that the absorber will suffer during the fall and therefore essential data to calculate the clearance distance. There is a lack of useful experimental data for the design of this personal protective equipment (PPE). This work provides empirical data required for the design of FAS with EAL in accordance with EN 355. This paper covers different types of EAL that are marketed internationally; different empirical data, average and maximum forces, required for improving safety design are researched. Six manufacturers, 10 models, and 2 samples of each model were selected, with total of 20 tests being performed. Dynamic performance tests were carried out, the free fall of a person was simulated using a 100 kg steel ballast from the maximum height allowed by the equipment, obtaining the maximum arrest force (Fm), average deployment force (Fa), and, by calculating the balance of forces, the maximum and average acceleration suffered by the ballast during its arrest. In light of the results, relevant conclusions for user safety are obtained. It is feasible to raise the safety requirements established by the different standards. The Fm can be established below 6 kN in the EAL, and the Fa can be estimated at 87.5% of the Fm. The categorization of the force–time curve in fall arrest with EAL has been obtained. Two EAL purchased on the market exceed the Fm permitted, therefore it is recommended to increase the quality controls of EAL.

scholarly journals Reversed-torsion-type crush energy absorption structure and its inexpensive partial-heating torsion manufacturing method based on origami engineering

2021 ◽  
pp. 1-31
Author(s):  
Xilu Zhao ◽  
Chenghai Kong ◽  
Yang Yang ◽  
Ichiro Hagiwara
Keyword(s):  
Energy Absorption ◽  
Peak Load ◽  
Point Of View ◽  
Building Structures ◽  
Manufacturing Method ◽  
Partial Heating ◽  
Vehicle Structure ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
Origami Engineering

Abstract Current vehicle energy absorbers face two problems during a collision in that there is only a 70% collapse in length and there is a high initial peak load. These problems arise because the presently used energy-absorbing column is primitive from the point of view of origami. We developed a column called the Reversed Spiral Origami Structure (RSO), which solves the above two problems. However, in the case of existing technology of the RSO, the molding cost of hydroforming is too expensive for application to a real vehicle structure. We therefore conceive a new structure, named the Reversed Torsion Origami Structure (RTO), which has excellent energy absorption in simulation. We can thus develop a manufacturing system for the RTO cheaply. Excellent results are obtained in a physical experiment. The RTO can replace conventional energy absorbers and is expected to be widely used in not only automobile structures but also building structures.

Design of a Hybrid Lightweight Energy Absorber

2016 ◽  
Vol 713 ◽  
pp. 321-324
Author(s):  
A. de Luca ◽  
Giuseppe Lamanna ◽  
Raffaele Sepe ◽  
Alessandro Soprano
Keyword(s):  
Kinetic Energy ◽  
Numerical Investigation ◽  
Structural Design ◽  
Carbon Composite ◽  
Energy Absorber ◽  
Load Paths ◽  
Passenger Safety ◽  
Carbon Composite Materials ◽  
Energy Absorbers ◽  
Energy Absorbing

Among several problems which might affect the passenger safety during an accidental crash event, the deceleration pulse is one of the most critical. For this reason vehicles are designed to convert the Kinetic Energy occurring in an impact in plastic deformation and to spread the loads due to such events through designed structural load paths. An important role in the kinetic energy absorbing at high velocities is played by the energy absorbers. The energy absorption capability of a crashworthy element or system is largely affected by material properties and structural design. This work deals with a numerical investigation on the energy absorbing capability of a new concept of energy absorber made out of the combination of metal parts and carbon composite materials. A numerical investigation on the parameters which increase the crash performance as well as decrease the weight of such device has been presented in this paper.

Smart Crash Management by Switching the Crash Behavior of Fiber-Reinforced Plastic (FRP) Energy Absorbers With Shape Memory Alloy (SMA) Wires

2013 ◽  
Author(s):  
Moritz Hübler ◽  
Sebastian Nissle ◽  
Martin Gurka ◽  
Sebastian Schmeer ◽  
Ulf Paul Breuer
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Essential Element ◽  
Load Level ◽  
Switching Behavior ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Energy Absorbers ◽  
Energy Absorbing

In this paper two innovative concepts for adjustable energy absorbing elements are presented. These absorbers can serve as an essential element in a smart crash management system e.g. for automotive applications. The adaptability is based on the basic idea of adjusting the stiffness of the absorber in relation to the actual load level in a crash event. Therefore the whole length of the absorber element can be used for energy dissipation. The adjustable absorbers are made from fiber reinforced plastics and shape memory alloy wires as actuating elements. Two possibilities for the basic design of the absorber elements are shown, the performance of the actuating SMA elements is characterized in detail and the switching behavior of the whole elements, between a stiff “on” state and a flexible “off” state, is measured.

Key Performance Indicators of Tubes Used as Energy Absorbers

2014 ◽  
Vol 626 ◽  
pp. 155-161 ◽  
Author(s):  
T.X. Yu ◽  
Yan Fei Xiang ◽  
Min Wang ◽  
Li Ming Yang
Keyword(s):  
Energy Absorption ◽  
Carrying Capacity ◽  
Performance Indicators ◽  
Key Performance Indicators ◽  
Absorption Capacity ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Engineering Designs ◽  
Energy Absorbers ◽  
Energy Absorbing

Based on our extensive studies on the experimental, theoretical and numerical results on various tubes under axial compression/impact in the last few years, we propose a set of Key Performance Indicators (KPIs) to assess and compare the energy absorbing performance of tubular structures with various configurations, so as to guide the design of energy absorbers whilst to archive a certain degree of optimization. The KPIs have five factors: Effective stroke ratio (ESR), Non-dimensional Load-carrying capacity (NLC), Effectiveness of energy absorption (EEA), Specific energy absorption capacity (SEA), Stableness of load-carrying capacity (SLC).The paper presents a series of diagrams to compare the energy absorbing performance of various tubes in terms of the four KPIs as described above. The work is valuable to engineering designs and applications, as well as to the further studies of the topic.

scholarly journals Energy Absorbing Effectiveness – Different Approaches

2018 ◽  
Vol 12 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Maria Kotełko ◽  
Mirosław Ferdynus ◽  
Jacek Jankowski
Keyword(s):  
Impact Load ◽  
Geometrical Parameters ◽  
Foam Filled ◽  
Thin Walled ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
Selection Of

AbstractIn the paper the study of different crashworthiness indicators used to evaluate energy absorbing effectiveness of thin-walled energy absorbers is presented. Several different indicators are used to assess an effectiveness of two types of absorbing structures, namely thin-walled prismatic column with flaws and thin-walled prismatic frustum (hollow or foam filled) in both cases subjected to axial compressive impact load. The indicators are calculated for different materials and different geometrical parameters. The problem of selection of the most appropriate and general indicators is discussed.

Insight Into the Design of Blast-Mitigating Floor Mats Using Design of Experiments

2019 ◽  
Author(s):  
Hisham Kamel
Keyword(s):  
Design Of Experiments ◽  
Computational Study ◽  
Close Contact ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Element Model ◽  
Influential Factor ◽  
Fe Model ◽  
Energy Absorbing ◽  
Insight Into

Abstract Recently, Improvised explosive devices (IEDs) have evolved into a major and significant threat inflicting substantial human casualties and property damage. The majority of injuries are to the lower extremities since they are in close contact to vehicle floor. Floor mats have been developed to mitigate the effects of IEDs blasts. This paper reports a computational study on the energy absorbing behavior of a novel commercial floor mat — Skydex — for foot protection. The design of experiments (DOE) approach was applied to investigate the effect of shape variations on the dynamic performance of a finite element model of Skydex. The FE model was verified using experimental tests on samples produced using 3D printing technique. The DOE approach revealed significant insight into the design of Skydex. It confirmed that shape variables have strong effect on the amount of energy absorbed and the transmitted load. DOE specifically identified the radius of the mid-section of Skydex as the most influential factor in controlling the mode of deformation under compression. In addition, it uncovered the interaction effect between the radius of curvatures of the two hemispheres and upper and lower radii. Finally, DOE revealed the bi-trade-off relations between energy absorbed, transmitted load and mass. These were shown in meaningful and helpful plots which will help the development of Skydex design.

Deformation and Energy Absorption of Steel Square Tubes With Optimized Shape Design

2019 ◽  
Author(s):  
Xiaofang Liu ◽  
Ziwen Fang ◽  
Haifeng Hong ◽  
Jianran Wang ◽  
Yanwen Liu ◽  
...  
Keyword(s):  
Impact Force ◽  
Longitudinal Direction ◽  
Axial Direction ◽  
Shape Design ◽  
Test Results ◽  
Element Analysis ◽  
Railway Vehicles ◽  
Side Walls ◽  
Energy Absorbers ◽  
Energy Absorbing

Abstract Square crush tubes have been widely used as impact energy absorbers in automotive and railway vehicles. In this paper, a square tube with vertical plates and dents has been designed to increase the controllability and stability of crash performance. Vertical plates are welded perpendicularly to the side walls of the tube, which increase the transverse stiffness and ensure the tube crashes in longitudinal direction under impact not in ideal axial direction. Dents have been put on the side walls near the front end of the tube to ensure the collapse always start from the front and progress gradually to the end. To validate the design, finite element analysis (FEA) and various experiments has been conducted and evaluated. Firstly, the numerical simulations were carried out using the software LS-DYNA. Then, four specimens were manufactured and tested. The crash velocity, tube deformation and impact force showed great agreement between the simulations and test results. The number of tubes, tube wall thickness, cross-section, trigger plates and dents arrangement can be adjusted to meet the requirements of different applications. In one application, the energy absorbing device with four crush tubes provided progressive controlled collapse with energy absorbing capacity of 1.22MJ and impact force less than 4450kN. This robust crush tube design has been successfully applied in multiple railway vehicles and also has the potential to be applied in other industries such as automotive vehicles.

Impact Response of Thin-Walled Tubes: A Prospective Review

2012 ◽  
Vol 165 ◽  
pp. 130-134 ◽  
Author(s):  
Fauziah Mat ◽  
K. Azwan Ismail ◽  
S. Yaacob ◽  
O. Inayatullah
Keyword(s):  
Compressive Loading ◽  
Axial Loading ◽  
Geometrical Parameters ◽  
Axial Deformation ◽  
Thin Walled Structures ◽  
Structural Applications ◽  
Thin Walled ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
The Impact

Thin-walled structures have been widely used in various structural applications asimpact energy absorbing devices. During an impact situation, thin-walled tubesdemonstrate excellent capability in absorbing greater energy through plastic deformation. In this paper, a review of thin-walled tubes as collapsible energy absorbers is presented.As a mean of improving the impact energy absorption of thin-walled tubes, the influence of geometrical parameters such as length, diameter and wall thickness on the response of thin-walled tubes under compression axial loading are briefly discussed. Several design improvements proposed by previous researchers are also presented. The scope of this review is mainly focus on axial deformation under quasi-static and dynamic compressive loading. Other deformations, such as lateral indentation, inversion and splitting are considered beyond the scope of this paper. This review is intended to assist the future development of thin-walled tubes as efficient energy absorbing elements.

An On-Water Analysis System for Quantifying Stroke Force Characteristics during Kayak Events

1992 ◽  
Vol 8 (2) ◽  
pp. 165-173 ◽  
Author(s):  
David A. Aitken ◽  
Robert J. Neal
Keyword(s):  
Data Acquisition ◽  
Water Analysis ◽  
Tape Recorder ◽  
System Software ◽  
Time Curve ◽  
Average Force ◽  
Force Transducers ◽  
Analysis System ◽  
Force Time ◽  
Force Characteristics

A system was developed to quantify the on-water forces, impulse, and power generated by a kayak paddlet. The system is lightweight (<1 kg), portable (i.e., it can be used in single [Kl], double [K2], and fours [K4] boats), and does not affect the integrity of either the kayak paddle or the boat. Changes in the strain on the kayak paddle were measured by force transducers attached to the shaft of the paddle, and these signals were then recorded on an FM tape recorder located in the boat. The data were then analyzed by the Kayak Data Acquisition and Analysis System software which graphically presented the paddlers' force time curve as well as a printed tabular report on the paddlers' average force, impulse, work, power, and the instantaneous boat velocity.

Sign in / Sign up

Export Citation Format

Share Document