Alan Lloyd, Eric Jacques, Omar Abdelalim, Murat Saatcioglu, Abass Braimah, Ghasan Doudak
Proceedings of the 2nd International Engineering Mechanics and Materials Specialty Conference, Ottawa, Canada, June, 2011
Publication year: 2011

Abstract: Design and construction of structures for blast safety requires an understanding of material properties under high rates of strain. A dynamic increase factor (DIF) – defined as the ratio of dynamic to static material property – is used to quantify the observed strain-rate dependence of material characteristics. The DIF is relatively well defined for common blast resistant construction materials, such as reinforced concrete and steel. However, little attention has been directed towards understanding the behaviour of wood members under rapid loading rates. A joint experimental research program between the University of Ottawa and Carleton University is currently underway to investigate the strain-rate dependence of the modulus of elasticity and modulus of rupture of sawn lumber specimens. A total of thirty-six Stud grade 2″×6” spruce-pine-fir (S-P-F) members were tested under four point bending at static and high strain-rates (on the order of 0.3 s -1 ). The University of Ottawa’s shock tube was used to generate shock wave loading while the static testing was carried out in the structures laboratory of Carleton University. Strains, displacements and applied loads were measured during static and high strain-rate testing. High speed video recordings of the response of the studs were also made and used to categorize failure modes. A single-degree-of-freedom numerical model was developed and used to characterize the material properties of S-P-F lumber under high rates of strain.

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