Methodology for Micromechanical Analysis of Wood Adhesive Bonds Using X-ray Computed Tomography and Numerical Modeling
Keywords:X-ray computed tomography, modeling, wood anatomy, digital image correlation, material point method
AbstractStructural performance of wood adhesive bonds depends on their ability to transfer stress across an interface of dissimilar materials, namely cell wall substance and cured polymeric adhesive. The interphase region of the bond consists of cell wall substance, voids, and voids filled with adhesive. In this study, an integrated method to numerically model micromechanical behavior of this system is described. The method includes micro-X-ray computed tomography (XCT) to define the three-dimensional (3D) structure of the bond on a micron scale. Tomography data were used as direct input to a micromechanics model. The model provided a 3D representation of equivalent strain and stress of the adhesive bond under load and, furthermore, integrated the microstructure of the interphase region into the solution. The model was validated using lap-shear test results from the same specimens that were scanned for XCT. Optical measurement and digital image correlation techniques provided full-field displacement data of the lap-shear specimen surfaces under load. Model simulation results compared favorably with measured surface displacements with spatial resolution in the micron range. The main advantage of the methodology is the accurate representation of the 3D microstructure of wood and the penetrating adhesive system in the numerical model.
Burvall A, Lundström U, Takman PAC, Larsson DH, Hertz HM (2011) Phase retrieval in X-ray phase-contrast imaging suitable for tomography. Opt Express 19(11):10359-10376.nChapman D, Thomlinson W, Johnston RE, Washburn D, Pisano E, Gmür N, Zhong Z, Menk R, Arfelli F, Sayers D (1997) Diffraction enhanced X-ray imaging. Phys Med Biol 42:2015-2025.nFrihart CR (2009) Adhesive groups and how they relate to the durability of bonded wood. J Adhes Sci Technol 23:601-617.nFuruno T, Immamura Y, Kajita H (2004) The modification of wood by treatment with low molecular weight phenol-formaldehyde resin: A properties enhancement with neutralized phenolic-resin and resin penetration into wood cell walls. Wood Sci Technol 37:349-361.nGibson LJ, Ashby MF (1997) Cellular solids: Structure and properties. Cambridge University Press, Cambridge, UK.nGindl W, Gupta HS (2002) Cell-wall hardness and Young's modulus of melamine-modified spruce wood by nanoindentation. Compos Part A-Appl S 33:1141-1145.nGindl W, Gupta HS, Schoberl T, Lichtenegger HL, Fratzl P (2004) Mechanical properties of spruce wood cell walls by nanoindentation. Appl Phys A-Mater 79(8):2069-2073.nHass P, Wittel FK, Mendoza M, Herrmann HJ, Niemz P (2012) Adhesive penetration in beech wood: Experiments. Wood Sci Technol 46:243-256.nJakes JE, Yelle DY, Beecher JF, Frihart CR, Stone DS. (2010) Characterizing polymeric methylene diphenyl diisocyanate reactions with wood: 2. Nano-indentation. Pages 366-373 in CR Frihart, CG Hunt, and RJ Moon, eds. Proc Wood Adhesives, 28-30 Sept. 2009, South Tahoe, NV. Forest Prod Soc, Madison, WI.nKamke FA, Lee JN (2007) Adhesive penetration in wood—A review. Wood Fiber Sci 39:205-220.nKamke FA, Modzel G, deCarlo F. (2010) Investigation of PF adhesive penetration in wood by micro x-ray tomography. Pages 343-347 in CR Frihart, CG Hunt, and RJ Moon, eds. Proc Wood Adhesives 2009, South Tahoe, NV, 28-30 Sept 2009. Forest Prod Soc, Madison, WI.nMiroy F, Eymard P, Pizzi A (1995) Wood hardening by methyoxymethyl melamine. Holz Roh Werkst 53(4):276.nModzel G (2009) Computed tomography analysis of wood-adhesive bonds. PhD dissertation, Oregon State University, Corvallis, OR. 219 pp.nModzel G, Kamke FA, deCarlo F (2011) Comparative analysis of a wood-adhesive bondline. Wood Sci Technol 45:147-158.nMomose A (2003) Phase-sensitive imaging and phase tomography using X-ray interferometers. Opt Express 11(19):2303-2314.nMüller U, Sretenovic A, Vincenti A, Gindl W (2005) Direct measurement of strain distribution along a wood bond line. Part 1: Shear strain concentration in a lap joint specimen by means of electronic speckle pattern interferometry. Holzforschung 59:300-306.nMuszyński L, Launey ME (2010) Advanced imaging techniques in wood-based panels research. Pages 177-201 in H Thoemen, M Irle, and M Sernek, eds. Wood-based panels—An introduction for specialists. COST Action E49 Workshop. Brunel University Press, London, UK.nNairn JA (2006) Numerical simulations of transverse compression and densification in wood. Wood Fiber Sci 38:576-591.nNairn JA (2011) Material point method (NairnMPM) and finite element analysis (NairnFEA) open-source software. http://code.google.com/p/nairn-mpm-fea/'>http://code.google.com/p/nairn-mpm-fea/nNIH. 2013. ImageJ Version 1.47i. National Institute of Health. http://imagej.nih.gov/ij/'>http://imagej.nih.gov/ij/nPfeiffer F, Weitkamp T, Bunk O, David C (2006) Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources. Nat Phys 2:258-261.nSerrano E, Enquist B (2005) Contact-free measurement and non-linear finite element analyses of strain distribution along wood adhesive bonds. Holzforschung 59:641-646.nTieman B (2007) HDF reader plug-in, Version 3.0, for ImageJ. Advanced Photon Source, Argonne National Laboratory, Argonne, IL.nUmemura K, Takahashi A, Kawai S (1998) Durability of isocycante resin adhesives for wood I: The properties of isocyanate resin cured with water. JWood Sci 44:204-210.nWilkins SW, Gureyev TE, Gao D, Pogany A, Stevenson AW (1996) Phase-contrast imaging using polychromatic hard X-rays. Nature 384:335-338.n
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