Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures

The specimen geometry has a significant influence on the Charpy impact strength. This is often a problem when it comes to the analysis of materials that can only be prepared with a curved shape, or which, like some biological structures, are naturally given in curved form like nutshells. The questio...

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Autores principales:	Nina Graupner, Niels Kühn, Jörg Müssig
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Charpy impact strength Curvature Curved impact test specimens Span length Sample thickness Notches Polymers and polymer manufacture TP1080-1185
Acceso en línea:	https://doaj.org/article/cb3fa3aa39a64b26ac4bd2a10c1e3a89
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id	oai:doaj.org-article:cb3fa3aa39a64b26ac4bd2a10c1e3a89
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spelling	oai:doaj.org-article:cb3fa3aa39a64b26ac4bd2a10c1e3a892021-11-24T04:23:32ZInfluence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures0142-941810.1016/j.polymertesting.2020.106864https://doaj.org/article/cb3fa3aa39a64b26ac4bd2a10c1e3a892021-01-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S0142941820320936https://doaj.org/toc/0142-9418The specimen geometry has a significant influence on the Charpy impact strength. This is often a problem when it comes to the analysis of materials that can only be prepared with a curved shape, or which, like some biological structures, are naturally given in curved form like nutshells. The question repeatedly arises to what extent the curvature influences the impact strength. Hence, the present study deals with the dependence of the specimen geometry like specimen thickness, curvature and notches on the impact properties of concrete, gypsum, polyurethane (PUR) and epoxy-based (EP) samples. Increasing sample thickness from 2 to 10 mm resulted in increased toughness for brittle materials, whereas more ductile materials did not show any significant change in toughness. Increasing span length showed an increase of the unnotched impact strength for brittle gypsum, while toughness increased for a more ductile PUR sample. For the curved specimens both, the unnotched and the notched Charpy impact strength could be shown to increase with a reduction of the specimen radius (higher curvature) while the notch-sensitivity was not significantly affected. Material-specific linear relationships between the impact strength and the curvature of the samples were found. These relationships were used to create a model to calculate the influence of the curvature on the impact strength. For all materials, the characteristic values of a normalised flat standard sample could be well predicted from measured values of curved specimens. This calculation approach was used to predict the impact strength of an isotropic biological sample (sweet potato) concerning a flat sample and different curved specimens. The results show a good trend with the measured values.Nina GraupnerNiels KühnJörg MüssigElsevierarticleCharpy impact strengthCurvatureCurved impact test specimensSpan lengthSample thicknessNotchesPolymers and polymer manufactureTP1080-1185ENPolymer Testing, Vol 93, Iss , Pp 106864- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Charpy impact strength Curvature Curved impact test specimens Span length Sample thickness Notches Polymers and polymer manufacture TP1080-1185
spellingShingle	Charpy impact strength Curvature Curved impact test specimens Span length Sample thickness Notches Polymers and polymer manufacture TP1080-1185 Nina Graupner Niels Kühn Jörg Müssig Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
description	The specimen geometry has a significant influence on the Charpy impact strength. This is often a problem when it comes to the analysis of materials that can only be prepared with a curved shape, or which, like some biological structures, are naturally given in curved form like nutshells. The question repeatedly arises to what extent the curvature influences the impact strength. Hence, the present study deals with the dependence of the specimen geometry like specimen thickness, curvature and notches on the impact properties of concrete, gypsum, polyurethane (PUR) and epoxy-based (EP) samples. Increasing sample thickness from 2 to 10 mm resulted in increased toughness for brittle materials, whereas more ductile materials did not show any significant change in toughness. Increasing span length showed an increase of the unnotched impact strength for brittle gypsum, while toughness increased for a more ductile PUR sample. For the curved specimens both, the unnotched and the notched Charpy impact strength could be shown to increase with a reduction of the specimen radius (higher curvature) while the notch-sensitivity was not significantly affected. Material-specific linear relationships between the impact strength and the curvature of the samples were found. These relationships were used to create a model to calculate the influence of the curvature on the impact strength. For all materials, the characteristic values of a normalised flat standard sample could be well predicted from measured values of curved specimens. This calculation approach was used to predict the impact strength of an isotropic biological sample (sweet potato) concerning a flat sample and different curved specimens. The results show a good trend with the measured values.
format	article
author	Nina Graupner Niels Kühn Jörg Müssig
author_facet	Nina Graupner Niels Kühn Jörg Müssig
author_sort	Nina Graupner
title	Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
title_short	Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
title_full	Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
title_fullStr	Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
title_full_unstemmed	Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures
title_sort	influence of sample thickness, curvature and notches on the charpy impact strength - an approach to standardise the impact strength of curved test specimens and biological structures
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/cb3fa3aa39a64b26ac4bd2a10c1e3a89
work_keys_str_mv	AT ninagraupner influenceofsamplethicknesscurvatureandnotchesonthecharpyimpactstrengthanapproachtostandardisetheimpactstrengthofcurvedtestspecimensandbiologicalstructures AT nielskuhn influenceofsamplethicknesscurvatureandnotchesonthecharpyimpactstrengthanapproachtostandardisetheimpactstrengthofcurvedtestspecimensandbiologicalstructures AT jorgmussig influenceofsamplethicknesscurvatureandnotchesonthecharpyimpactstrengthanapproachtostandardisetheimpactstrengthofcurvedtestspecimensandbiologicalstructures
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Influence of sample thickness, curvature and notches on the Charpy impact strength - An approach to standardise the impact strength of curved test specimens and biological structures

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