Schlüsselwörter
(Deutsch)
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Yew wood; spruce wood; micromechanics; elasticity; toughness
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Forschungsprogramme
(Englisch)
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COST-Action E35 - Fracture mechanics and micromechanics of wood and wood composites with regard to wood machining
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Kurzbeschreibung
(Deutsch)
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Im Rahmen dieses Projektes soll zum einen eine hochzähe Holzart (Eibe) mit einer Holzart mit eher sprödem Bruchverhalten (Fichte) hinsichtlich ihrer mechanischen Eigenschaften, ihrer Bruchmechanik und ihres mikroskopischen und submikorskopischen Aufbaus verglichen und untersucht werden. Die Untersuchungen sollen auf verschiedenen hierarchischen Ebnenen (Vollholz, Mikrozugproben (Dünnschnitte) und Einzelfasern) durchgeführt werden. Ein Ziel des Projektes ist es, zwischen den mechanischen Eigenschaften und dem Versagensverhalten zum einen und dem Holzaufbau zum anderen eine Verbindung herzustellen.
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Partner und Internationale Organisationen
(Englisch)
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AT, CH, DE, DK, ES, FI, FR, GR, HR, HU, IT, NO, PL, PT, RO, RS, SE, SI, UK
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Abstract
(Englisch)
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For centuries, Common yew (Taxus baccata L.) has been well known for its extraordinary longitudinal elasticity and toughness. Among other things, its wood was used for certain historical weapons (longbows, lances, crossbows) requiring these material properties, particularly the low Young's modulus and at the same time a high stretchability parallel to the grain. The few available literature references also indicate a high elasticity. Indisputably, there are further elastic softwood species, but none of them have a similarly high raw density as yew. Thus, yew holds an exceptional position, especially since there is usually a strong species-spanning positive interrelation between density and Young's modulus. The reasons for this compliant mechanical response of yew despite its high density were as yet unknown. Consequently, the objectives of this experimentally oriented project were: 1) to characterize the elasto-mechanical behaviour of solid yew wood in the three principle growth directions; 2) to determine the longitudinal Young's moduli at different hierarchical levels; 3) to find structure-property relations that may explain the high longitudinal compliance; 4) to investigate, by means of selected examples, how structural features of yew effect its fracture behaviour. So to serve as a reference species, all investigations were also applied to spruce (Picea abies [L.] Karst.) with its raw density being about one third lower than that of yew.
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Datenbankreferenzen
(Englisch)
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Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. +41 31 322 74 82 Swiss Project-Number: C03.0018
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