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Session 29 ic2011 kamke
 

Session 29 ic2011 kamke

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    Session 29 ic2011 kamke Session 29 ic2011 kamke Presentation Transcript

    • Frederick A. Kamke1, Josef Weissensteiner 1,2 and Hongling Lui 1,3 1 Oregon State University, Corvallis, Oregon USA 2 Universität für Bodenkultur , Vienna, Austria 3 Northwest A&F University, Yangling, Shanxi, P.R. ChinaForest Products Society 65th International Convention June 19-21, 2001, Portland, Oregon
    • AbstractWood modification technology has created opportunities to expandthe application of structural wood composites. Previously, woodcomposites had mechanical properties that were limited by theproperties of the virgin wood. Typically, properties of the composite,such as OSB, plywood, and LVL, are less than the properties of thevirgin wood due to process-induced damage or limitations of adhesivebonding. However, composites have the advantage of reducedvariability, and consequently, engineering design values for thecomposite are often greater than comparable solid wood products.Wood modification technology can increase strength and stiffness ofwood three to four times above virgin timber. While wood modificationincreases processing cost, strategic composite design minimizes finalproduct cost by minimizing the amount of modified wood required. Inaddition, modification techniques may upgrade low quality veneer thatpreviously was not suited for structural composites. This presentationsummarizes applications of wood modification technology in thedesign of a laminated composite.
    • Manufacture high value composite materials from rapid-grown, under-utilized and sustainable forest resources.11-year hybrid poplar Courtesy of APA The Engineered Wood Association
    • Densification of wood by mechanical compressioninto thin lamina using rapid processing technologyand lamination to produce engineered composites. • Damage of wood during densification • Dimensional stability • Adhesive bonding • Manufacturing cost
    • Densification of wood by mechanical compressioninto thin lamina using rapid processing technologyand lamination to produce engineered composites. • Wood densification • Thermo-mechanical compression • Thermo-hydro-mechanical (THM) compression • Viscoelastic thermal compression (VTC) • And others
    • Manufacture structural composite materials from rapid-grown and sustainable forest resources. I-Beams Bridge Structures Transportation Vehicles Structural PanelsLaminated Engineered Wood Concrete FormsVeneer Lumber Flooring Wind Turbine Blades
    • • Perpendicular to grain• Wood above glass transition temperature• Minimal to no cell wall fracture• Can be performed in a few minutes
    • • Radiata pine (Pinus radiata)• Loblolly pine (Pinus taeda)• Douglas-fir (Pseudotsuga menziesii)• Western hemlock (Tsuga heterophylla)• Alaska cedar (Chamaecyparis nootkatensis)• Yellow-poplar (Liriodendron tulipifera)• Aspen (Populus tremuloides)• Sweetgum (Liquidambar styraciflua)• Paulownia (Paulownia tomentosa)• Eastern Cottonwood (Populus deltoides)• Hybrid poplar clones (Populus sp.)• Maple (Acer sp.)• Red oak (Quercus rubra)
    • Green Building Materials Laboratory
    • Sealed Chamber Max. Steam Pressure: 150 psi Max. Compression: 3000 psi Platen Size: 10 in. x 24 in. Stainless-Steel Bellows, 28 in ØInterior: Electrically-Heated Platens with Water Cooling
    • Electrically-Heated & Lid Sample Water Cooled PlatensSteam Vent InletThermal Insulation Stainless-Steel Bellows SIDE VIEW of CHAMBER
    • Typical Process Schedule TEMPERATURE 170oC WOOD THICKNESS <10 mm COMPRESSION FORCE 800 psi TIME 125 psi STEAM PRESSURE CONDITIONING TIME COMPRESSION TIME COOLING TIME
    • Example: Hybrid Poplar - Effect of Compression Time UNTREATED
    • Number of plies = 16 Non-VTC MOE = 11 GPa VTC MOE = 25 GPa LVL MOE = 15 GPa 2 VTC Plies38.1 mm 14 Non-VTC Plies 2 VTC Plies 30% increase of MOE with 25% VTC by weight
    • 100 95 Hybrid Poplar & Phenol-Formaldehyde Effective Adhesive Penetration (mm) 80 60 41 40 30 23 20 0 0 63 98 132 Densification (%)Kutnar et al (2008) Wood and Fiber Sci. 40(3):362-373
    • Example: Hybrid poplar ASTM D905 Shear in Compression Loading
    • 3-Point Bending UNTREATED UNTREATED • Brittle failures common • No delaminations
    • FSpecific Gravity: Untreated = 0.37, VTC = 1.2 D h Hybrid Poplar HB = F / (p  D  h) D = 10 mm F = 500 N (112 lbf) Rautkari, Kamke & Hughes, 2011, Wood Sci. & Tech.
    • FSpecific Gravity: Untreated = 0.37, VTC = 1.2 D h Hybrid Poplar HB = F / (p  D  h) D = 10 mm F = 500 N (112 lbf) Rautkari, Kamke & Hughes, 2011, Wood Sci. & Tech.
    • Design by Corvallis Tool Company Annealing ZoneCooling Zone Conditioning Zone Compression Zone
    • • Densification possible without cell wall fracture.• Thin lamina may be processed in short time.• Energy cost approximately same as conventional veneer processing by substitution of drying step.• Densified wood bonds well and consumes much less adhesive.• Dimensional stability controlled by heat treatment or chemical treatments, if needed.• Brittle failure could be a problem in critical structural applications.• Manufacturing cost higher than conventional veneer processing, but significant value added in process.
    • USDA Wood Utilization Research Center Special GrantJELD-WEN FoundationOregon BEST