Grading of sawn timber using the vibration technique: locating imperfections based on flexural mode shapes
2011 (English)In: 17th international nondestructive testing and evaluation of wood symposium / [ed] Ference Divos, Sopron, Hungary: University of West Hungary , 2011, 269-276 p.Conference paper (Refereed)
The present study aims at investigating the potential of using mode shape or mode shape curvature (MSC) for detecting defects in wooden beams. It includes modal analysis, Finite Element (FE) modeling and visual scanning. An FE model was created to investigate the effect of defects of different size and location on the mode shape/MSC. The mode shape/MSC showed a good potential to be used for finding defects. An experimental study on 17 boards of Norway spruce, dimensions of 50×150×3900 mm, was conducted using experimental modal analysis. The findings reveal that: (1) the mode shape/MSC studied in the FE-model could be used to locate defects, (2) the method is very sensitive to measurement noise and it requires an accurately measured mode shape, (3) an error analysis shows that it is not possible to achieve the accuracy needed using accelerometers.
Place, publisher, year, edition, pages
Sopron, Hungary: University of West Hungary , 2011. 269-276 p.
experimental modal analysis, finite element modeling, mode shape, mode shape curvature, resonance frequency, strength grading, visual scanning
Research subject Technology (byts ev till Engineering), Civil engineering; Technology (byts ev till Engineering), Forestry and Wood Technology
IdentifiersURN: urn:nbn:se:lnu:diva-15747ISBN: 978-963-9883-81-9OAI: oai:DiVA.org:lnu-15747DiVA: diva2:455252
17th international nondestructive testing and evaluation of wood symposium