Cushion foundations: rigid expanded polystyrene foam as a deforming and cushioning layer

2000 ◽  
Vol 4 (1) ◽  
pp. 3-12 ◽  
Author(s):  
G. Beinbrech ◽  
F. Hohwiller
Keyword(s):  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam

A machine learning approach to estimate the strain energy absorption in expanded polystyrene foams

2021 ◽  
pp. 0021955X2110210
Author(s):  
Alejandro E Rodríguez-Sánchez ◽  
Héctor Plascencia-Mora
Keyword(s):  
Neural Network ◽  
Energy Absorption ◽  
Mechanical Energy ◽  
Compressive Loading ◽  
Ground Truth ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Stress Strain ◽  
Ground Truth Data ◽  
Expanded Polystyrene Foam

Traditional modeling of mechanical energy absorption due to compressive loadings in expanded polystyrene foams involves mathematical descriptions that are derived from stress/strain continuum mechanics models. Nevertheless, most of those models are either constrained using the strain as the only variable to work at large deformation regimes and usually neglect important parameters for energy absorption properties such as the material density or the rate of the applying load. This work presents a neural-network-based approach that produces models that are capable to map the compressive stress response and energy absorption parameters of an expanded polystyrene foam by considering its deformation, compressive loading rates, and different densities. The models are trained with ground-truth data obtained in compressive tests. Two methods to select neural network architectures are also presented, one of which is based on a Design of Experiments strategy. The results show that it is possible to obtain a single artificial neural networks model that can abstract stress and energy absorption solution spaces for the conditions studied in the material. Additionally, such a model is compared with a phenomenological model, and the results show than the neural network model outperforms it in terms of prediction capabilities, since errors around 2% of experimental data were obtained. In this sense, it is demonstrated that by following the presented approach is possible to obtain a model capable to reproduce compressive polystyrene foam stress/strain data, and consequently, to simulate its energy absorption parameters.

Theoretical and experimental study of width effects on horizontal flame spread over extruded and expanded polystyrene foam surfaces

2013 ◽  
Vol 32 (3) ◽  
pp. 193-209 ◽  
Author(s):  
Lin Jiang ◽  
Huahua Xiao ◽  
Yang Zhou ◽  
Weiguang An ◽  
Weigang Yan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flame Spread ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam

scholarly journals Energy Performance Assessment of Waste Materials for Buildings in Extreme Cold and Hot Conditions

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3131 ◽  
Author(s):  
Yasir Rashid ◽  
Fadi Alnaimat ◽  
Bobby Mathew
Keyword(s):  
Date Palm ◽  
Concrete Block ◽  
Climatic Conditions ◽  
Expanded Polystyrene ◽  
Waste Materials ◽  
Geopolymer Concrete ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam ◽  
Rubber Tire ◽  
By Products

In this article, thermal performance of different waste materials and by-products of industrial processes is investigated experimentally. A geopolymer concrete block with 7.5 cm thickness and cross-sectional area of 5 × 5 cm was considered as a reference model to measure heat transmission across the two opposite surfaces while all four remnant surfaces were perfectly insulated. For all other samples, a sandwich concrete block was developed by taking two pieces of the geopolymer concrete with 2.5 cm thickness each on either side and insulation material of 2.5 cm thickness in between. The sandwich materials investigated were air cavity, expanded polystyrene foam, polyurethane foam, rubber tire, date palm, PCM-30, and PCM-42. Experimental investigations revealed that the investigated green materials and industrial by-products have comparable insulation performance with respect to the traditional insulations such as expanded polystyrene foam. It is found that polyurethane foam and date palm can reduce indoor cooling demand by 46.6% each in hot conditions while rubber tire can reduce indoor heating demand by 59.2% in cold climatic conditions at the maximum. The research results confirm and encourage the effective utilization of waste materials in building walls for reducing indoor air-conditioning demand in the extreme climatic conditions.

Effect of polymer foam anisotropy on energy absorption during combined shear-compression loading

2017 ◽  
Vol 54 (3) ◽  
pp. 597-613 ◽  
Author(s):  
Yasmine Mosleh ◽  
Kelly Vanden Bosche ◽  
Bart Depreitere ◽  
Jos Vander Sloten ◽  
Ignaas Verpoest ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Transverse Shear ◽  
Axial Loading ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Polymer Foam ◽  
Expanded Polystyrene Foam ◽  
Shear Loads ◽  
Loading Direction ◽  
Compression Behaviour

Polymeric foams are extensively used in applications such as packaging, sports goods and sandwich structures. Since in-service loading conditions are often multi-axial, characterisation of foams under multi-axial loading is essential. In this article, quasi-static combined shear-compression behaviour of isotropic expanded polystyrene foam and anisotropic polyethersulfone foam was studied. For this, a testing apparatus which can apply combined compression and transverse shear loads was developed. The results revealed that the shear and compression energy absorption, yield stress and stiffness of foams are dependent on deformation angle. The total energy absorption of the anisotropic polyethersulfone foam is shown to be direction dependent in contrast to isotropic expanded polystyrene. Furthermore, for similar relative density, polyethersulfone foam absorbs more energy than expanded polystyrene foam, regardless of deformation angle. This study highlights the importance of correct positioning of foam cells in anisotropic foams with respect to loading direction to maximise energy absorption capability.

Preparation of microencapsulated phase change materials based on expanded polystyrene foam wastes

2018 ◽  
Vol 13 (7) ◽  
pp. 998-1000 ◽  
Author(s):  
Yifei Shao ◽  
Haifeng Jiang ◽  
Shu Li ◽  
Jiaqi Yang ◽  
Mingyue Zhang ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam ◽  
Microencapsulated Phase Change Materials

Density Variation in the Expanded Polystyrene Foam of Bicycle Helmets and Its Influence on Impact Performance

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Shannon G. Kroeker ◽  
Muammer Ç. Özkul ◽  
Alyssa L. DeMarco ◽  
Stephanie J. Bonin ◽  
Gunter P. Siegmund
Keyword(s):  
Head Injury ◽  
Density Variation ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Head Impacts ◽  
Impact Performance ◽  
Expanded Polystyrene Foam ◽  
Bicycle Helmets ◽  
Pilot Work ◽  
The Relationship

Abstract Bicycle helmets attenuate head impacts using expanded polystyrene (EPS) foam liners. The EPS density plays a key role in determining the helmet and head response during an impact. Prior pilot work in our lab showed that EPS density varied by up to 18 kg/m3 within a single helmet, and thus the purpose of this study was to quantify the regional density variations within and between helmets and to establish how these variations influence helmet impact performance. We evaluated 10–12 samples of two traditional and two bicycle motocross (BMX) bicycle helmets with EPS liners. The bulk liner density and density of 16–19 cores extracted from specific locations on each sample were measured. Additional samples of two of these helmet models were then impacted at 3.0, 6.3, and 7.8 m/s to determine the relationship between local EPS density and helmet impact performance. We found that density varied significantly within each sample in all helmet models and also varied significantly between samples in three helmet models. The density variations were not symmetric across the midline in two of the four helmet models. The observed density variations influenced the helmets' impact performance. Our data suggest that variations in peak headform acceleration during impacts to the same location on different samples of the same helmet model can be partially explained by density differences between helmet samples. These density variations and resulting impact performance differences may play a role in a helmet's ability to mitigate head injury.

Numerical analysis of energy absorption in expanded polystyrene foams

2019 ◽  
Vol 56 (4) ◽  
pp. 411-434
Author(s):  
Alejandro E Rodríguez-Sánchez ◽  
Héctor Plascencia-Mora ◽  
Elías R Ledesma-Orozco ◽  
Eduardo Aguilera-Gómez ◽  
Diego A Gómez-Márquez
Keyword(s):  
Finite Element ◽  
Stress Response ◽  
Finite Element Model ◽  
Energy Absorption ◽  
Material Model ◽  
Element Model ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Loading Rates ◽  
Expanded Polystyrene Foam

The expanded polystyrene foam is widely used as a protective material in engineering applications where energy absorption is critical for the reduction of harmful dynamic loads. However, to design reliable protective components, it is necessary to predict its nonlinear stress response with a good approximation, which makes it possible to know from the engineering design analysis the amount of energy that a product may absorb. In this work, the hyperfoam constitutive material model was used in a finite element model to approximate the mechanical response of an expanded polystyrene foam of three different densities. Additionally, an experimental procedure was performed to obtain the response of the material at three loading rates. The experimental results show that higher densities at high loading rates allow better energy absorption in the expanded polystyrene. As for the energy dissipation, high dissipation is obtained at higher densities at low loading rates. In the numerical results, the proposed finite element model presented a good performance since root mean square error values below 9% were obtained around the experimental compressive stress/strain curves for all tested material densities. Also, the prediction of energy absorption with the proposed model was around a maximum error of 5% regarding the experimental results. Therefore, the prediction of energy absorption and the compressive stress response of expanded polystyrene foams can be studied using the proposed finite element model in combination with the hyperfoam material model.

scholarly journals Characterization of the Tensile Behavior of Expanded Polystyrene Foam as a Function of Density and Strain Rate

2020 ◽  
Vol 22 (12) ◽  
pp. 2000794
Author(s):  
Dimitris Zouzias ◽  
Guido De Bruyne ◽  
Ramon Miralbes ◽  
Jan Ivens
Keyword(s):  
Strain Rate ◽  
Expanded Polystyrene ◽  
Tensile Behavior ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam

Decoupling shear and compression properties in composite polymer foams by introducing anisotropy at macro level

2018 ◽  
Vol 37 (10) ◽  
pp. 657-667
Author(s):  
Yasmine Mosleh ◽  
Bart Depreitere ◽  
Jos Vander Sloten ◽  
Jan Ivens
Keyword(s):  
Biaxial Loading ◽  
Stress Component ◽  
Single Layer ◽  
Shear Resistance ◽  
Expanded Polystyrene ◽  
Macro Level ◽  
Polystyrene Foam ◽  
Composite Foam ◽  
Expanded Polystyrene Foam ◽  
Compression Properties

Anisotropy in foams generally originates from cell elongation in a certain direction. In this study, a composite concept is utilized to create anisotropy in foams at macro level. For this, layered composite foam is proposed by combining discrete layers of expanded polystyrene foam foam with different densities. The layers are positioned in parallel with the prime loading direction. The compression and biaxial combined shear-compression behavior of the composite foams are studied and compared with single-layer expanded polystyrene foam of equivalent density. The biaxial shear-compression test results demonstrate that the composite concept enables to decouple shear and compression properties of foam for a given overall density. In compression loading, the composite foam behavior is similar to that of single-layer foam of similar density, while in biaxial loading, the composite foam shows lower shear resistance than single-layer foam. Moreover, in biaxial loading, parameters such as the number of layers and the density difference between the high- and low-density layers affect the extent of decrease in shear resistance, while the compression stress component depends solely on the overall density of the composite foam. One of the potential applications of this behavior could be in protective helmets for mitigation of the head rotational acceleration.

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