Optimization of machine strength grading of structural timber by means of bending MOE profiles with high resolution
2013 (English)In: Proceedings of the 18th International Nondestructive Testing and Evaluation of Wood Symposium, Madison, Wisconsin, USA, September 24−27, 2013, Madison: USDA (United States Department of Agriculture), Forest Service, Forest Products Laboratory , 2013, 396-403 p.Conference paper (Refereed)
Most machine strength grading methods are based on rather poor statistical relationships between edgewise bending strength and modulus of elasticity (MOE), the latter determined either as flatwise bending MOE measured over a length of about one meter, or as global axial dynamic MOE. Furthermore, European Standards stipulate that local MOE in both edgewise bending and tension shall be determined at a critical section and over a length of five times the depth of the piece. However, a study of tensile strain fields determined on side board surfaces using contact-free measurement technique showed that stiffness reduction occurs very locally. This characteristic was used for development of a new indicating property (IP) defined as local edgewise bending MOE and determined by means of scanned fibre direction fields and stiffness integration over cross-sections. A maximum coefficient of determination equal to 0.77 was obtained between strength and such an IP determined over a length of about the member’s half depth.
Place, publisher, year, edition, pages
Madison: USDA (United States Department of Agriculture), Forest Service, Forest Products Laboratory , 2013. 396-403 p.
coefficient of determination, contact-free, fibre angle, indicating property, laser scanning, machine strength grading, strain fields
Building Technologies Wood Science
Research subject Technology (byts ev till Engineering), Civil engineering
IdentifiersURN: urn:nbn:se:lnu:diva-33388OAI: oai:DiVA.org:lnu-33388DiVA: diva2:708687
18th International Nondestructive Testing and Evaluation of Wood Symposium, Madison, WI, USA, September 24-27, 2013.