Problems Associated with Testing the Impact Absorption Properties of Artificial Playing Surfaces

2009 ◽  
pp. 77-77-8
Author(s):  
RB Martin
Keyword(s):  
Absorption Properties ◽  
The Impact ◽  
Impact Absorption

scholarly journals EXPERIMENTAL EVALUATION OF THE IMPACTABSORPTION PROPERTIES OF RUBBER TILES FOR THE PLAYGROUND

2004 ◽  
Vol 16 (05) ◽  
pp. 244-250 ◽  
Author(s):  
LI-TUNG CHANG ◽  
KUEN-HORNG TSAI ◽  
JIN-SHAN SHIAU
Keyword(s):  
Head Injury ◽  
Head Injuries ◽  
Peak Acceleration ◽  
Critical Height ◽  
Shock Absorption ◽  
Absorption Properties ◽  
Head Injury Criterion ◽  
The Impact ◽  
Impact Absorption ◽  
Base Structure

Rubber tiles are popular in playgrounds as protective surfacing to reduce the incidence of head injuries caused by children falling from equipment. However, Taiwan has not yet established a test code for assessment of the shock-absorption properties of such surfacing. For this study, an experimental model was established to evaluate the behavior of various rubber tiles. A hemispherical headform was dropped from a set height to strike the center of the specimen tile. The peak acceleration and Head Injury Criterion (HIC) were measured to assess the impact absorption of and critical height for a given rubber tile. The results show that utilization of the HIC index provides a more conservative assessment of the shock absorption and, ultimately, protection from head injuries than peak acceleration. The maximum critical heights of the rubber tiles used in this study for tile thicknesses of 45, 60 and 80 mm were 1.6, 2.0 and 2.2 m, respectively. Two-part rubber tiles with a base structure consisting of a box-like core offer superior protection from head injuries relative to analogous cylindrical, square pillar and solid structures. The maximum differences in peakacceleration and HIC values comparing the box-like core and solid structures at a thickness of 45 mm were 21% and 44%, respectively. The results of this study suggest a minimum of rubber thickness of 60 mm, based on probable maximum fall heights of more than 1.6 m. Moreover, incorporation of an appropriate cushioning structure in the base of the rubber tile could further improve protection.

A Study Into LDPE as an Undersurfacing Material for Injury Prevention and Risk Minimisation in Children’s Playgrounds

2003 ◽  
Author(s):  
David Eager
Keyword(s):  
Injury Prevention ◽  
Test Method ◽  
Risk Minimisation ◽  
Absorption Properties ◽  
Closed Cell ◽  
Height Of Fall ◽  
Absorbing Material ◽  
The Impact ◽  
Impact Absorption ◽  
Cell Foam

Low Density Polyethylene (LDPE) closed-cell foam is used extensively as an impact absorbing material for injury prevention and risk minimisation in a variety of applications, including children’s playground undersurfacing, padding for trampoline frames, and other fall zones. This paper presents and analyses the data from numerous impact tests performed on samples of LDPE of select different product thicknesses (10, 20, 30 and 40 mm), nominal Relative Densities (30, 45, 60 and 75 kg/m3) and drops or free height of fall (100 mm steps in heights from 300 to 2100 mm). The impact absorption properties of LDPE are characterized using the Australian and New Zealand Standard AS/NZS 4422: Playground Surfacing — Specifications, Requirements and Test Method. The gmax and HIC results are presented both graphically and numerically. This paper also discusses uses and limitations of LDPE with particular emphasis on injury prevention and risk minimisation.

scholarly journals Lay-up optimisation of fibre–metal laminates panels for maximum impact absorption

2020 ◽  
Vol 54 (29) ◽  
pp. 4591-4609
Author(s):  
Edore G Arhore ◽  
Mehdi Yasaee
Keyword(s):  
Fibre Orientation ◽  
Second Step ◽  
Finite Element Models ◽  
Absorption Properties ◽  
Fibre Metal Laminates ◽  
Design Variables ◽  
Fibre Metal ◽  
The Impact ◽  
Optimisation Procedure ◽  
Impact Absorption

This paper introduces a methodology utilising a ply-ply damage Finite Element models with Genetic algorithm optimisation procedure to investigate the effect of lay-up configuration on the impact absorption properties of fibre metal laminates (FMLs). The methodology was carried out in two steps. In the first step, a pseudo-2D model was used to explore the vast design space to identify potential optimised layup-configurations. In the second step, the optimised configurations were studied in full 3 D, with high fidelity simulations, verifying the results obtained from the optimisation process. The design variables used include thickness and material (including fibre orientation) of each ply. The results produced an optimised configuration consisting of a metallic ply on the impacted side followed by a cross-ply composite lay-up. The results also suggest that the first composite ply (second ply of the FML) should be about 3 times thicker than the other plies.

scholarly journals Cellulose Nanofibrils/Xyloglucan Bio-Based Aerogels with Shape Recovery

Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Samuel Mandin ◽  
Samuel Moreau ◽  
Malika Talantikite ◽  
Bruno Novalès ◽  
Jean-Eudes Maigret ◽  
...  
Keyword(s):  
Water Absorption ◽  
Shape Recovery ◽  
Cellulose Nanofibrils ◽  
High Water ◽  
Absorption Capacity ◽  
Absorption Properties ◽  
High Affinity ◽  
High Water Absorption ◽  
Freezing Procedure ◽  
The Impact

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.

scholarly journals Testing the Force Absorption of Composite Materials to Select the Best for Making a Helmet

2021 ◽  
Vol 15 (4) ◽  
pp. 581-584
Author(s):  
Božo Bujanić ◽  
Matija Košak
Keyword(s):  
Carbon Fibers ◽  
Material Selection ◽  
Glass Fibers ◽  
Test Procedure ◽  
Test Results ◽  
Aramid Fibers ◽  
Absorption Properties ◽  
Eu Project ◽  
Impact Absorption ◽  
The Eu

The paper presents and describes the procedure of testing the materials that were available for the production of a multifunctional protective helmet. The procedure was carried out at the company Šestan-Busch d.o.o. as part of the EU project for the development and production of a multifunctional protective helmet. The test results showed that carbon fibers polymers as a composite material have the best impact absorption properties which was a key criterion for material selection. Other materials; glass fibers polymers, aramid fibers polymers and combinations in the test procedure showed worse results compared to the selected criterion.

Study on Ductile Brittle Transition Temperature of Q345C Steel MAG Welded Joints

2016 ◽  
Vol 703 ◽  
pp. 155-159
Author(s):  
Yong Shou Wu ◽  
Yong Jun Liu
Keyword(s):  
Transition Temperature ◽  
Low Temperature ◽  
Weld Seam ◽  
Brittle Transition ◽  
Absorption Energy ◽  
Ductile Brittle Transition Temperature ◽  
Brittle Transition Temperature ◽  
Impact Absorption Energy ◽  
The Impact ◽  
Impact Absorption

For Q345C steel MAG welded joints, low temperature tensile test was carried out at normal atmospheric temperature, 0°C,-20°C,-30°C and-40°C in the paper, which results in the law of strength change with temperature. The impact absorption energy of the weld seam sample under different temperature conditions was tested, impact fracture morphology was observed and the parentage of the fibrous fracture surface was assessed. The curve of impact absorption energy and the percentage of the fibrous fracture surface with temperature were fitted by using the Boltzmann function, and ductile brittle transition temperature of Q345C steel MAG welded joints was determined. The test results show that the impact absorption energy of the weld seam can reach 71J at-40°C, and the weld seam is prone to brittle fracture under low temperature. The influences of alloying elements and microstructure on the ductile brittle transition temperature and low temperature impact toughness were discussed, and suggestion is put forward to improve the impact toughness and reduce the ductile brittle transition temperature.

Subsea-Asset Protection From Falling Objects Using Multi-Layered Shielding: A Preliminary Study

2017 ◽  
Author(s):  
Cheslav Balash ◽  
Guy MacLean ◽  
David MacLean
Keyword(s):  
Thin Shell ◽  
Shock Loading ◽  
Impact Force ◽  
Concrete Strength ◽  
Absorption Properties ◽  
Asset Protection ◽  
Relative Absorption ◽  
Series Of Experiments ◽  
Preliminary Study ◽  
The Impact

Protection solutions for pipelines, umbilicals, and cables from accidentally dropped objects are generally implemented with concrete mattresses, though concrete does not effectively dissipate shock loading. The presented work investigated relative absorption properties of two materials (concrete and polystyrene), singly and in combination, with an aim to ultimately advance the protection of subsea assets from falling objects. A series of experiments were undertaken to measure the impact force from dropped objects of varied mass and height on single and stacked plates of varied thickness. It was concluded that the combination of absorptive and non-absorptive materials could be beneficial; specifically, a protection shield for a subsea asset could comprise concrete at the base, polystyrene through the middle, and a thin shell layer of concrete on the outer surface. The proposed next phase will seek the combination of concrete strength and polystyrene compression to provide optimum levels of absorption.

Light absorption properties, chromophore composition and sources of brown carbon aerosol in Xi’an, Northwest China

2020 ◽  
Author(s):  
Ru-Jin Huang ◽  
Wei Yuan ◽  
Lu Yang ◽  
Jie Guo ◽  
Jing Duan ◽  
...  
Keyword(s):  
Light Absorption ◽  
Coal Combustion ◽  
Radiative Forcing ◽  
Northwest China ◽  
Absorption Efficiency ◽  
Vehicular Emissions ◽  
Absorption Properties ◽  
Seasonal Differences ◽  
Brown Carbon ◽  
The Impact

<p>The impact of brown carbon aerosol (BrC) on the Earth’s radiative forcing balance has been widely recognized but remains uncertain, mainly because the relationships among BrC sources, chromophores, and optical properties of aerosol are poorly understood (Feng et al., 2013; Laskin et al., 2015). In this work, the light absorption properties and chromophore composition of BrC were investigated for samples collected in Xi’an, Northwest China from 2015 to 2016. Both absorption Ångström exponent and mass absorption efficiency show distinct seasonal differences, which could be attributed to the differences in sources and chromophore composition of BrC. Three groups of light-absorbing organics were found to be important BrC chromophores, including those show multiple absorption peaks at wavelength > 350 nm (12 polycyclic aromatic hydrocarbons and their derivatives) and those show single absorption peak at wavelength < 350 nm (10 nitrophenols and nitrosalicylic acids and 3 methoxyphenols). These measured BrC chromophores show distinct seasonal differences and contribute on average about 1.1% and 3.3% of light absorption of methanol-soluble BrC at 365 nm in summer and winter, respectively, about 7 and 5 times higher than the corresponding mass fractions in total organic carbon. The sources of BrC were resolved by positive matrix factorization (PMF) using these chromophores instead of commonly used non-light absorbing organic markers as model inputs. Our results show that in spring vehicular emissions and secondary formation are major sources of BrC (~70%), in fall coal combustion and vehicular emissions are major sources (~70%), in winter biomass burning and coal combustion become major sources (~80%), while in summer secondary BrC dominates (~60%).</p><p> </p><p>References:</p><p>Feng, Y., V. Ramanathan, and V. R. Kotamarthi: Brown carbon: A significant atmospheric absorber of solar radiation?, Atmos. Chem. Phys., 13, 8607-8621, doi:10.5194/acp-13-8607-2013, 2013.</p><p>Laskin, A., J. Laskin, and S. A. Nizkorodov: Chemistry of atmospheric brown carbon, Chem. Rev., 115, 4335-4382, doi:10.1021/cr5006167, 2015.</p>

Effect of Casting Method and Al Contents on Microstructure in AM-Type Magnesium Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 663-666 ◽  
Author(s):  
Katsumi Watanabe ◽  
Kenji Matsuda ◽  
Takumi Gonoji ◽  
Tokimasa Kawabata ◽  
Katsuya Sakakibara ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Hardness Test ◽  
Al Alloys ◽  
Age Hardening ◽  
Casting Method ◽  
Absorption Properties ◽  
Al Content ◽  
Hardening Behavior ◽  
The Difference ◽  
Impact Absorption

Magnesium alloys have received considerable attention because of their lightweight and recyclability. AM-type and AZ-type Mg-Al alloys have been used for industrial products widely, particularly for AM-type alloys because of the better toughness and impact absorption properties than AZ-type alloys. However, there is little report about the effect of casting method on age-hardening behavior and microstructure of AM-type alloys. The purpose of this study is to investigate the difference of the age-hardening behavior and microstructures of three AM-type alloys cast with steel, copper and sand molds using hardness test and scanning electron microscopy (SEM) observation. Furthermore, the effect of Al content is also investigated in this study using three alloys of AM30 (3%Al), AM60 (6%Al) and AM90 (9%Al).

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