Compression of polystyrene and polypropylene foams for energy absorption applications: A combined mechanical and microstructural study

Andena, Luca; Caimmi, Francesco; Leonardi, L.M.; Nacucchi, Michele; Pascalis, Fabio De

doi:10.1177/0021955x18806794

Cited by 50 publications

(44 citation statements)

References 27 publications

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“…This response has its explanation in the rate-dependency of the EPS foam as pointed out in the study by Avalle et al 28 for foam-type materials, i.e., when they deform, the air or gas contained in the cells is compressed or forced outside, letting a fluid flow, dependent on the compression rate, to drive the macro response of the material. As for the effect that the density has in the stress response, the results are consistent with what it is reported and explained thoroughly in the materials foam literature, 11,26,29 i.e., the material shows a stiffer response at high densities.…”

Section: Discussionsupporting

confidence: 89%

“…10 The mechanical response of the EPS material has been extensively studied utilizing analytical and numerical modeling of its micromechanical structure. Andena et al 11 found that the Gibson-Ashby model 9 can provide reasonable approximations for the first and the second stress stages for most foams of study, including the EPS. Such a model has also been applied to study the macro response of the EPS for constant strain rate conditions.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of energy absorption in expanded polystyrene foams

Rodríguez-Sánchez

Mora

Orozco

et al. 2019

Journal of Cellular Plastics

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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.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of energy absorption in expanded polystyrene foams

Rodríguez-Sánchez

Mora

Orozco

et al. 2019

Journal of Cellular Plastics

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“…Kinetic energy-absorbing capability on the right level is very important, because values of the peak force and acceleration over the threshold could cause injury or damage. Energy absorbed during single or multiple impacts can be described in several ways [ 1 , 2 , 3 ]. For example, as a relation between peak impact deceleration of the real foam and “ideal” foam, and the ability to completely absorb impact energy.…”

Section: Introductionmentioning

confidence: 99%

“…An extensive data set acquired at different strain rates is needed to cover application requirements for particular material use. The material structure and the strain rate of polymer foams was considered by Luca Andena et al They have used Nagy’s phenomenological model and determined the material stress–strain behaviour at a reference strain rate [ 3 ]. To predict foam behaviour under specific conditions and optimizing design of energy absorption devices, various models were developed, trying to capture actual material mechanics.…”

Section: Introductionmentioning

confidence: 99%

Static Mechanical Properties of Expanded Polypropylene Crushable Foam

et al. 2021

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Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

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“…The dynamic cushion factors of expanded polyethylene foams range from 3.95 to 4.70 depending on the density of EPE. 16,19 The C* value of the 3D printed foam in this study was approximately 3.27 before densification (Table 2).…”

Section: Resultsmentioning

confidence: 56%

Damping and cushioning characteristics of Polyjet 3D printed photopolymer with Kelvin model

Cormier

Rice

2020

Journal of Cellular Plastics

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This study extends previous research on the measurement of a 3D printed photopolymer’s quasi-static cushion properties, to include cushion and damping properties due to impact loading. In order to develop analytical packaging models of 3D printed materials, it is essential to know how energy induced by shipping and handling is dissipated through damping. Compared to the cushion curve, investigating how damping influences packaging design is relatively unfamiliar to the packaging practitioner. This study uses experimentally derived hysteresis loops, from platen impact and quasi-static compression tests, to estimate specific damping capacities for 3D printed photopolymer. This study found that the “sticky” rubber like 3D printed photopolymers, based on a repeating pattern of Kelvin cells, were able to dissipate close to 100% of the input energy in platen impact tests and still return to their original dimensions after impact. In addition, this study shows that the specific damping capacity of the 3D printed structure increases significantly with strain rate.

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Compression of polystyrene and polypropylene foams for energy absorption applications: A combined mechanical and microstructural study

Cited by 50 publications

References 27 publications

Numerical analysis of energy absorption in expanded polystyrene foams

Numerical analysis of energy absorption in expanded polystyrene foams

Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Damping and cushioning characteristics of Polyjet 3D printed photopolymer with Kelvin model

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