European Journal of Wood and Wood Products

, Volume 69, Issue 4, pp 605–617 | Cite as

Assessment of glued timber integrity by limited-angle microfocus X-ray computed tomography

  • Sergio J. Sanabria
  • Peter Wyss
  • Juerg Neuenschwander
  • Peter Niemz
  • Urs Sennhauser
Originals Originalarbeiten

Abstract

Glued timber products have an extensive range of applications in construction. In this work a Microfocus X-ray Computed Tomography method was developed to inspect gluing defects in timber samples and was applied successfully on experimental data. The bonding plane was segmented into glued and non-glued regions and imaged with 5 mm resolution. Moreover, the gap topology between timber lamellas was precisely characterised. A limited-angle reconstruction with anisotropic frame binning together with a specific glue line readout method efficiently filters out undesired wood structure highlighting the information of the adhesive joint. This method imposes limitations on the size of the specimen in only one dimension. The presence and absence of glue could be detected for glue line thicknesses over 50 μm and air gaps larger than 150 μm could be characterised. Several information reduction approaches were combined in the reconstruction process to implement the assessment of a 100×100 mm2 bonding plane in less than 40 s.

Detektion von Fehlverklebungen in Holzbauteilen mittels Mikrofokus Röntgen-Computertomographie

Zusammenfassung

Holzverklebungen gewinnen zunehmend an Bedeutung. Im Rahmen dieser Arbeit wurde ein Mikrofokus Röntgen-Computertomographie Messverfahren zur Beurteilung von Fehlverklebungen in Holzbauteilen entwickelt und in experimentellen Versuchen erfolgreich überprüft. Fehlverklebungen und die Topologie der Klebfugen wurden mit einer räumlichen Auflösung von 5 mm abgebildet. Verfahrensspezifische Bildrekonstruktions- und Klebfugen-Auslesealgorithmen mit eingeschränktem Aufnahmewinkelbereich filtern unerwünschte Holzstrukturen heraus und heben die Leimschicht hervor. Die Größe der Holzbauteile ist bei diesem Messverfahren nur in einer Dimension beschränkt. Die An- und Abwesenheit von Klebstoff lässt sich für Leimfugen dicker als 50 μm nachweisen; Luftspalten größer als 150 μm sind feststellbar. Die Informations-Reduktionsverfahren ermöglichten die Beurteilung von 100×100 mm2 verleimten Holzoberflächen in einer Messzeit von weniger als 40 s.

References

  1. Archibald R, Gelb A (2002) A method to reduce the Gibbs ringing artifact in MRI scans while keeping tissue boundary integrity. IEEE Trans Med Imaging 21(4):305–319 PubMedCrossRefGoogle Scholar
  2. Berglind H, Dillenz A (2003) Detection of glue deficiency in laminated wood with pulse thermography. J Wood Sci 49(3):216–220 Google Scholar
  3. Bhandarkar SM, Luo XZ, Daniels R, Tollner EW (2006) A novel feature-based tracking approach to the detection, localization, and 3-D reconstruction of internal defects in hardwood logs using computer tomography. Pattern Anal Appl 9(2–3):155–175 CrossRefGoogle Scholar
  4. Bucur V (2003) Nondestructive characterization and imaging of wood. Springer, Berlin Google Scholar
  5. Choi MY, Park JH, Kim WT, Kang KS (2008) Detection of delamination defect inside timber by sonic IR. In: Proc of the Society of Photo-optical Instrumentation Engineers (SPIE), Orlando, FL, USA, 6939 U306-U309 Google Scholar
  6. Dill-Langer G, Aicher S, Bernauer W (2005) Reflection measurements at timber glue-lines by means of ultrasound shear waves. Otto-Graf-J 16:273–283 Google Scholar
  7. Dunky M, Niemz P (2002) Holzwerkstoffe und Leime: Technologie und Einflussfaktoren. Springer, Berlin CrossRefGoogle Scholar
  8. EN 386:2001 Glued laminated timber—Performance requirements and minimum production requirements Google Scholar
  9. EN 391:2001 Glued laminated timber—Delamination test of glue lines Google Scholar
  10. EN 14080:2005 Timber structures—Glued laminated timber—Requirements Google Scholar
  11. Entacher K, Planitzer D, Uhl A (2007) Towards an automated generation of tree ring profiles from CT-images. In: Proc of the 5th international symposium on image and signal processing and analysis, New York, NY, USA, pp 174–179 CrossRefGoogle Scholar
  12. Espinoza GR, Hernandez R, Condal A, Verret D, Beauregard R (2005) Exploration of the physical properties of internal characteristics of sugar maple logs and relationships with CT images. Wood Fiber Sci 37(4):591–604 Google Scholar
  13. Feldkamp LA, Davis LC, Kress JW (1984) Practical cone-beam algorithm. J Opt Soc Am A, Opt Image Sci Vis 1(6):612–619 CrossRefGoogle Scholar
  14. Hasenstab A (2006) Integritätsprüfung von Holz mit dem zerstörungsfreien Ultraschallechoverfahren. Dissertation, Technische Universität Berlin Google Scholar
  15. Hu LJ, Gagnon S (2007) X-ray-based scanning technique for non-destructive evaluation of finger-joint strength. In: Proc of the 15th international symposium on NDT of wood, Deluth, MN, USA Google Scholar
  16. Kabir MF, Schmoldt DL, Schafer ME (2002) Time domain ultrasonic signal characterization for defects in thin unsurfaced hardwood lumber. Wood Fiber Sci 34(1):165–182 Google Scholar
  17. Kak AC, Slaney M (1988) Principles of computerized tomographic imaging. IEEE Press, New York Google Scholar
  18. Longuetaud F, Mothe F, Leban JM (2007) Automatic detection of the heartwood/sapwood boundary within Norway spruce (Picea abies (L) Karst) logs by means of CT images. Comput Electron Agric 58:100–111 CrossRefGoogle Scholar
  19. Maeva E, Severina I, Bondarenko S, Chapman G, O’Neill B, Severin F, Maev RG (2004) Acoustical methods for the investigation of adhesively bonded structures: a review. Can J Phys 82(12):981–1025 CrossRefGoogle Scholar
  20. Mannes D, Sonderegger W, Hering S, Lehmann E, Niemz P (2009a) Non-destructive determination and quantification of diffusion processes in wood by means of neutron imaging. Holzforschung 63(5):589–596 CrossRefGoogle Scholar
  21. Mannes D, Niemz P, Lehmann E (2009b) Tomographic investigations of wood from macroscopic to microscopic scale. Wood Res 54(3):33–44 Google Scholar
  22. Morigi MP, Casali F, Bettuzzi M, Bianconi D, Brancaccio R, Cornacchia S, Pasini A, Rossi A, Aldrovandi A, Cauzzi D (2007) CT investigation of two paintings on wood tables by Gentile da Fabriano. Nucl Instrum Methods Phys Res, Sect A, Accel Spectrom Detect Assoc Equip 580(1):735–738 CrossRefGoogle Scholar
  23. Niemz P, Kucera LJ, Flisch A, Blaser E (1997) Application of computertomography (CT) on wood defects and decay. Holz Roh- Werkst 55:279–280 CrossRefGoogle Scholar
  24. Niemz P, Poblete H, Cuevas H, Flisch A (1999) Klebfugenfestigkeit von keilverzinktem. Holzforsch Holzverwert 51:79–81 Google Scholar
  25. Oja J (2000) Evaluation of knot parameters measured automatically in CT-images of Norway spruce (Picea abies (L) Karst). Holz Roh- Werkst 58(5):375–379 CrossRefGoogle Scholar
  26. Osterloh K, Raedel C, Zscherpel U, Meinel D, Ewert U, Buecherl T, Hasenstab A (2008) Fast neutron radiography and tomography of wood. Insight 50(6):307–311 CrossRefGoogle Scholar
  27. Rinnhofer A, Petutschnigg A, Andreu JP (2003) Internal log scanning for optimizing breakdown. Comput Electron Agric 41(1–3):7–21 CrossRefGoogle Scholar
  28. Sanabria SJ, Mueller C, Neuenschwander J, Niemz P, Sennhauser U (2010a) Air-coupled ultrasound as an accurate and reproducible method for bonding assessment of glued timber. Wood Sci Technol. doi:10.1007/s00226-010-0357-z Google Scholar
  29. Sanabria SJ, Neuenschwander J, Niemz P, Sennhauser U (2010b) Structural health monitoring of glued laminated timber with a novel air-coupled ultrasound method. In: Proc of the 11th World conference on timber engineering, Riva del Garda, Trentino, Italy Google Scholar
  30. Scheepers G, Moren T, Rypstra T (2007) Liquid water flow in Pinus radiata during drying. Holz Roh- Werkst 65(4):275–283 CrossRefGoogle Scholar
  31. Schmoldt DL, He J, Abbott AL (2000) Automated labeling of log features in CT imagery of multiple hardwood species. Wood Fiber Sci 32(3):287–300 Google Scholar
  32. Sepulveda P, Oja J, Gronlund A (2002) Predicting spiral grain by computed tomography of Norway spruce. J Wood Sci 48(6):479–483 Google Scholar
  33. Sharp GC, Kandasamy N, Singh H, Folkert M (2007) GPU-based streaming architectures for fast cone-beam CT image reconstruction and demons deformable registration. Phys Med Biol 52(19):5771–5783 PubMedCrossRefGoogle Scholar
  34. Sirr SA, Waddle JR (1999) Use of CT in detection of internal damage and repair and determination of authenticity in high-quality bowed stringed instruments. Radiographics 19(3):639–646 PubMedGoogle Scholar
  35. Solodov I, Pfleiderer K, Busse G (2004) Nondestructive characterization of wood by monitoring of local elastic anisotropy and dynamic nonlinearity. Holzforschung 58(5):504–510 CrossRefGoogle Scholar
  36. Van Trees HJ (2001) Detection, estimation and modulation theory, Part I. Wiley, New York CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Sergio J. Sanabria
    • 1
  • Peter Wyss
    • 1
  • Juerg Neuenschwander
    • 1
  • Peter Niemz
    • 2
  • Urs Sennhauser
    • 1
  1. 1.Electronics/Metrology/Reliability Laboratory, EmpaSwiss Federal Laboratories for Materials Science and TechnologyDuebendorfSwitzerland
  2. 2.Institute for Building Materials, Wood PhysicsETH ZurichZurichSwitzerland

Personalised recommendations