This paper presents a comparative study using static and ultrasonic testing for the determination of the full set of orthotropic material properties of wood. In the literature, material properties are typically only available in the longitudinal direction, and most international standards do not provide details on the testing of the other two secondary directions (radial and tangential). This work provides a comprehensive study and discussions on the determination of all twelve orthotropic material properties of two hardwood species using static testing and an alternative testing approach based on ultrasonic waves. Recommendations are given on the execution of the tests and the interpretation and calibration of the results.
This paper presents an investigation of using different material testing approaches to determine material properties of timber utility poles from two hardwood tree species, i.e. Spotted Gum and Tallowwood. The material properties investigated are the Modulus of Electricity (MOE), the Modulus of Rupture (MOR) and the compression strength (CS) in longitudinal direction as well as radial and tangential directions of the cross section of the poles. These material properties are needed for the accurate modelling of timber poles using Finite Element Method (FEM) for the study of stress wave propagation and damage detection in timber utility poles. In open literatures, for most timber species such comprehensive material property data are scarce to find. Typically, material properties available are only in the longitudinal direction. Furthermore, most international standards cover only details on material testing in longitudinal direction and no coherent nor comprehensive guidelines are given for the testing of the full orthotropic material properties of timber. Hence, an extensive study is deemed necessary to investigate a suitable approach to determine full material properties of timber. Two hardwood timber species, namely Spotted Gum and Tallowwood are selected for this investigation. Beside full material properties, the investigation is extended to examine different material testing approaches (bending, compression and tension testing) for the determination of the same material properties. The presented material testing is conducted on numerous small clear specimens as well as on four full scale 5 m long timber pole specimens of the two mentioned hardwood tree species.
Der Beitrag behandelt das in der Psychologie seit Langem diskutierte Phänomen, dass das Wissen um den Ausgang eines bestimmten Schadensereignisses die nachträgliche Beurteilung von dessen Voraussehbarkeit signifikant beeinflusst. Der Autor widmet sich der Frage, ob diese Erkenntnisse Einfluss auf unsere Dogmatik der strafrechtlichen Fahrlässigkeitsdelikte haben und falls ja, wie diese zu vermeiden wären. Er kommt zur Einsicht, dass die oft als debiasing-Methode diskutierte Zweiteilung des Prozesses weder über das Tatinterlokut noch über das Erfolgsinterlokut befriedigend gelöst werden kann. Sobald der Strafrichter mit einer Fahrlässigkeitstat befasst ist, weiss er, dass ein Erfolg eingetreten ist, da die folgenlose Fahrlässigkeit nicht strafbar ist. Der Autor schlägt deshalb eine andere Methode zur Vermeidung des Rückschaufehlers vor.
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