Thermal conductivity of anisotropic, inhomogeneous high‐density foam calculated from three‐dimensional reconstruction of microtome images

Hegdal, Jan Peder; Tofteberg, Terje; Schjelderup, Trond; Hinrichsen, Einar L.; Grytten, Frode; Echtermeyer, Andreas T.

doi:10.1002/app.39238

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…The foamed layer material appears to be graded meaning that the porous structure varies along one or more of the spatial dimensions of the material. These trends are also consistent with the work done by Hegdal et al [31].…”

Section: Morphological Variationssupporting

confidence: 93%

“…Cellular materials of various densities are used as impact protection in many applications [21] -and this portion of the multi-layer coating system is therefore of particular interest in mitigating pipeline impacts. Hegdal et al [31] documented significant variation in mass density over the thickness of their coating. As mechanical properties of such materials are often found to be dependent on mass density [21], upsetting tests have been conducted on foamed specimens in order to study possible variations in material behavior throughout the coating layer.…”

Section: Generalmentioning

confidence: 98%

“…The insulating layer makes up over 80% of the design's total coating thickness and is produced in an extrusion process where a propylene copolymer known as BA202E [30] is combined with the foaming agent SAFOAM FP-40 to form the foamed structure. Hegdal et al [31] studied the variation in thermal conductivity due to changing the pore morphology over the thickness of a similar coating solution. Therein, microtome images where collected from a coating specimen, revealing an anisotropic and inhomogeneous internal pore structure.…”

Section: Generalmentioning

confidence: 99%

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Quasi-static and dynamic indentation of offshore pipelines with and without multi-layer polymeric coating

et al. 2018

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Offshore pipelines are occasionally subjected to accidental impact loads from trawl gear or anchors, which may damage the pipe. In this study, a series of indentation experiments carried out on offshore steel pipes covered by a multi-layer polymeric coating solution is presented. Polymeric coating solutions are often applied to pipelines to act as corrosion protection and thermal insulation. Despite not being designed for it, the polymeric coatings are experienced to have an energy absorbing capacity, which is the main topic of the investigation herein. In design codes and guidelines, coatings are traditionally not accounted for when determining the energy absorbed by a pipeline during impact. This makes estimates overly conservative. The main goal of this experimental work is thus to investigate the contribution a typical polymeric coating makes to the energy absorption in a pipeline during impact. To this end, a series of indentation experiments carried out on offshore steel pipes covered by a multi-layer polymeric coating solution is performed. The test program includes quasi-static and dynamic denting experiments on both coated and uncoated full-scale pipe cross-sections. All pipes tested have a length of approximately 1 m. The sharpest indenter from the relevant guidelines is used, as a sharp indenter is more likely to penetrate the coating compared with a blunter one. Based on the outcome of the tests, the polymeric coating is found to absorb a considerable amount of the kinetic energy delivered by an impacting object.

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Section: Morphological Variationssupporting

confidence: 93%

Section: Generalmentioning

confidence: 98%

Section: Generalmentioning

confidence: 99%

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Quasi-static and dynamic indentation of offshore pipelines with and without multi-layer polymeric coating

et al. 2018

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“…This local response may explain why EPP foams strain harden more in the plateau region than XPS foams, and is probably a consequence of the production process. Since XPS foams are extruded, the density will vary over the thickness, and is often found to be lower in the center of the material [42]. EPP foams, on the other hand, are expanded resulting in a more evenly distributed density.…”

Section: Resultsmentioning

confidence: 99%

Quasi-static behaviour of crash components with steel skins and polymer foam cores

Reyes

2018

Materials Today Communications

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Different types of crash components are extensively used by the automotive industry to absorb energy during car accidents. Such components typically consist of sandwich structures with thin metal or composite plates as skins and a cellular foam as core to dissipate the energy. In this study, the quasi-static behaviour of two types of polymeric foams with different densities, namely extruded polystyrene (XPS) and expanded polypropylene (EPP), utilized as core material in a crash component, has been investigated. First, an extensive material test program involving compression tests on cubic specimens loaded in different material directions was carried out to reveal the mechanical properties of the foams. Second, quasi-static impact tests were conducted on various target configurations consisting of 0.8 mm thick skins of Docol 600DL steel and the various foam materials as core. In these tests, the applied force and the displacement of the striker were registered by the test machine, while digital cameras and 3D-DIC were used to measure the back-plate out-of-plane displacement of the various components.It seems clear from the presented results that if low weight combined with maximum energy absorption are the primary interests, an XPS foam as core seems to be beneficial, while if force reduction and minimum back-plate displacement are most important, an EPP foam as core seems to be a better choice. Thus, the response of the crash component is largely determined by the properties of the core material during quasi-static loading.

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“…Diamond knives are better suited to harder samples, but there is a cost implication, and they can cost many £1000s. Recently, researchers have been using (ultra)microtomes for human‐made materials, 18,27,28 with further examples using a cryogenic ultramicrotome to cut a mudrock for AFM analysis, 26 molluscan shells cut into 5–8 μm sections using a microtome, 29 and pipe foam insulation cut into 150 μm slices using a microtome 30 . So it is certainly possible to use (ultra)microtomes for harder, human‐made materials, however the knife choice and run setup will be key.…”

Section: Discussionmentioning

confidence: 99%

Methods to expose subsurface objects of interest identified from 3D imaging: The intermediate sample preparation stage in the correlative microscopy workflow

Mitchell

Dunlop

Volkenandt

et al. 2022

Journal of Microscopy

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The correlative imaging workflow is a method of combining information and data across modes (e.g. SEM, X‐ray CT, FIB‐SEM), scales (cm to nm) and dimensions (2D–3D–4D), providing a more holistic interpretation of the research question. Often, subsurface objects of interest (e.g. inclusions, pores, cracks, defects in multilayered samples) are identified from initial exploratory nondestructive 3D tomographic imaging (e.g. X‐ray CT, XRM), and those objects need to be studied using additional techniques to obtain, for example, 2D chemical or crystallographic data. Consequently, an intermediate sample preparation step needs to be completed, where a targeted amount of sample surface material is removed, exposing and revealing the object of interest. At present, there is not one singular technique for removing varied thicknesses at high resolution and on a range of scales from cm to nm. Here, we review the manual and automated options currently available for targeted sample material removal, with a focus on those methods which are readily accessible in most laboratories. We summarise the approaches for manual grinding and polishing, automated grinding and polishing, microtome/ultramicrotome, and broad‐beam ion milling (BBIM), with further review of other more specialist techniques including serial block face electron microscopy (SBF‐SEM), and ion milling and laser approaches such as FIB‐SEM, Xe plasma FIB‐SEM, and femtosecond laser/LaserFIB. We also address factors which may influence the decision on a particular technique, including the composition, shape and size of the samples, sample mounting limitations, the amount of surface material to be removed, the accuracy and/or resolution of peripheral parts, the accuracy and/or resolution of the technique/instrumentation, and other more general factors such as accessibility to instrumentation, costs, and the time taken for experimentation. It is hoped that this study will provide researchers with a range of options for removal of specific amounts of sample surface material to reach subsurface objects of interest in both correlative and non‐correlative workflows.

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Thermal conductivity of anisotropic, inhomogeneous high‐density foam calculated from three‐dimensional reconstruction of microtome images

Cited by 8 publications

References 16 publications

Quasi-static and dynamic indentation of offshore pipelines with and without multi-layer polymeric coating

Quasi-static and dynamic indentation of offshore pipelines with and without multi-layer polymeric coating

Quasi-static behaviour of crash components with steel skins and polymer foam cores

Methods to expose subsurface objects of interest identified from 3D imaging: The intermediate sample preparation stage in the correlative microscopy workflow

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