Quasi-Static Axial Crushing Behavior of Aluminum Closed Cell Foam-Filled Multi-Packed Aluminum and Composite/ Aluminum Hybrid Tubes

The concerns of automotive safety have been given special attention in order to reduce human fatalities or injuries. One of the techniques to reduce collision impact or compression energy is by filling polymeric foam into metallic tubes. In this work, polyurethane foam was introduced into the steel extrusion tubes and quasi-statically compressed at constant cross-head displacement. Different tube thicknesses and foam densities were used and these parameters were related to the crashworthiness aspect of the foam-filled structures. It is found that both tube thickness and foam density played an important role in increasing the crashworthiness behaviours of the structures but when the tube thickness reached certain value, foam density unable to properly work in increasing the energy absorption of the structures.

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Complementary and normalized energies during static and dynamic uniaxial deformation of single and multi-layer foam-filled tube

Journal of Sandwich Structures & Materials ◽

10.1177/10996362211050914 ◽

2021 ◽

pp. 109963622110509

Author(s):

Seyed Mohammad Hossein Mirbagheri ◽

Mina Salehi

Keyword(s):

Dynamic Test ◽

A356 Alloy ◽

Single Layer ◽

Thin Wall ◽

Dynamic Tests ◽

Static Tests ◽

Closed Cell ◽

Foam Filled ◽

Crushing Behavior ◽

Energy Absorbing

This article investigates the quasi-static compressive behavior and the drop weight impact tests during the crashing of energy-absorbing structures such as aluminum foam-filled tubes. The closed-cell Al and A356 Alloy foams were cast and, after cutting, inserted into the Al thin wall tube as axial fillers of single-, double- and quad-layer structures. Then, the specific energy absorption (SEA), complementary energy (CE), normalized energy (NE), and specific normalized energy (SNE) are calculated based on static and dynamic test results under uniaxial loading. In this new method, values of NE and SNE are always between 0 and 1. Results show that the SEA-strain curves obtained from crashing the foam-filled tubes were linear and overlapping under static and dynamic loading. However, NE curves for dynamic tests were cyclic and in the static tests were asymptotic non-linear, and utterly separable. Results indicated that the SNE for Al, A356 single layer, Al-A356 double-, and Al-A356-Al-A356 quad-layer foam-filled tubes during dynamic tests were 0.25, 0.29, 0.31, and 0.31, while for the static tests, 0.14,0.15, 0.17, and 0.14 were recorded. It was found that CE and NE energies were better than the SEA energy for recognizing plastic deformation and crushing behavior.

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Temperature dependency of the long-term thermal conductivity of spray polyurethane foam

Journal of Building Physics ◽

10.1177/17442591211045415 ◽

2021 ◽

pp. 174425912110454

Author(s):

Neal Holcroft

Keyword(s):

Thermal Conductivity ◽

Polyurethane Foam ◽

Cellular Structure ◽

Gas Diffusion ◽

Temperature Dependent ◽

Blowing Agent ◽

Closed Cell ◽

Wall Assembly ◽

Cell Foam

The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.

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Study of Physical Properties and Shock Absorption Abilities of Starch Polymer Foam as Cushioning Material for Packaging

MATEC Web of Conferences ◽

10.1051/matecconf/201822506010 ◽

2018 ◽

Vol 225 ◽

pp. 06010

Author(s):

N. Amir ◽

Mohamed Syakir Mohamed Hisham ◽

Kamal Ariff Zainal Abidin

Keyword(s):

Average Density ◽

Curing Process ◽

Polymer Foam ◽

Shock Absorption ◽

Open Cell ◽

Lack Of Information ◽

Closed Cell ◽

Open Cell Foam ◽

Cell Foam ◽

Cushioning Material

Lack of information about the formulation and fabrication process of starch polymer foam and lack of study in the shock absorption ability of starch polymer foam were the reasons this research was executed. In this project starch polymer foam was produced to be used as cushioning material for packaging. Starch polymer foam were developed from starch, polyvinyl alcohol (PVA), urea, citric acid, and deionised water. Water amount with drying and curing process were the variables manipulated to produce the best starch polymer foam. It was determined then, that the optimized ratio of starch:PVA:citric acid was 1:1:4. The amount of water used was 10 ml/gram of starch/PVA weight. The suitable foaming mixing was done at a speed of 1500 rpm for 40 minutes. Drying process was done at 70°C for 24 hours, followed by curing process at 100°C for 1 hour to produce closed-cell foam. While for the open-cell foam, the foam was dried and cured at 100ºC for 6 hours. The open-cell and closed-cell foams produced were cut to 6 cm height x 6 cm width x 0.5 cm thick. The average density was calculated and then the foams were subjected to weight drop destructive test. The test was done by placing a foam on top of a piece of mirror, and a weight is dropped onto the foam, with increasing height until the mirror break. Three weights were used with mass of 50 g, 100 g and 200 g. The starch foams were compared to polyurethane and polystyrene foams in terms of the minimum height that can cause the mirror to break. The results showed that starch closed-cell foam absorbed the highest impact energy followed by polystyrene foam, starch open-cell foam and polyurethane foam.

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Open-Cell Foam Metal Production and Characterization by Aluminum Solid Mold Investment Casting

Encyclopedia of Aluminum and Its Alloys ◽

10.1201/9781351045636-140000238 ◽

2019 ◽

Author(s):

Kerem Altug Guler

Keyword(s):

Investment Casting ◽

Replication Process ◽

Open Cell ◽

Metal Fabrication ◽

Cell Structures ◽

Closed Cell ◽

Small Complex ◽

Open Cell Foam ◽

Foam Metal ◽

Cell Foam

Foam metals can be categorized in two basic classes: open-cell and closed-cell structures, which both have different numerous unique properties. Up to the present, several production processes have been developed for each class. Investment casting is known as a replication process for open-cell foam metal fabrication. Solid mold, which can be evaluated as a subtechnique of the investment casting, is specialized especially for small complex shapes with ultrathin sections. This work is a presentation of aluminum open-cell foam production with solid mold investment casting using two different kinds of patterns. The first one is “burnable,” in which liquid metal directly fills the shape of pattern and the second is “leachable,” in which metal takes the form of intergranular network shape of porous salt preforms.

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Experimental Study on Impact Damage of Concrete Bridge Pier with Closed-cell Foam Aluminum Buffer Materials

Proceedings of the 2017 International Conference Advanced Engineering and Technology Research (AETR 2017) ◽

10.2991/aetr-17.2018.31 ◽

2018 ◽

Author(s):

Xiwu Zhou ◽

Kai Zhao ◽

BenYing Wu ◽

WenChao Zhang

Keyword(s):

Experimental Study ◽

Impact Damage ◽

Bridge Pier ◽

Concrete Bridge ◽

Foam Aluminum ◽

Closed Cell ◽

Cell Foam

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Microstructural and Chemical Analysis of Polyurethane and Polyisocyanurate Foam Insulations

10.32920/ryerson.14651922.v1 ◽

2021 ◽

Author(s):

Umberto Berardi

Keyword(s):

Thermal Conductivity ◽

Thermal Performance ◽

Cell Structure ◽

Polymer Degradation ◽

Chemical Characterization ◽

Aging Behavior ◽

Blowing Agent ◽

Closed Cell ◽

Physical Attributes ◽

Cell Foam

For some closed cell foam insulation products, the thermal conductivity increases at low temperatures, contrary to single thermal resistance values provided by manufacturers. This phenomenon has been demonstrated in various polyurethane and polyisocyanurate insulations. The reduction in thermal performance has been attributed to the diffusion of air and blowing agent through the foam and to the condensation of blowing agent. Aging processes such as freeze-thaw cycling, moisture accumulation, and polymer degradation further increase thermal conductivity. The initial cell structure plays a role in dictating the thermal performance. To further understand the loss of thermal performance in closed cell foams, microstructure and chemical characterization was performed in this study. The aging behavior of foam insulations was analyzed by imaging foams with SEM and by measuring foam. Changes in the polymer physical attributes were identified and compared to increases in thermal conductivity. This project also used gas chromatography and quantified changes in pentane concentration in polyisocyanurate foams that have undergone aging

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