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TRACHEID EFFECT SCANNING AND EVALUATION OF IN-PLANE AND OUT-OF-PLANE FIBER DIRECTION IN NORWAY SPRUCE TIMBER

Andreas Briggert, Min Hu, Anders Olsson, Jan Oscarsson

Abstract


Local fiber direction is decisive for both strength and stiffness in timber. In-plane fiber direction on surfaces of timber can be determined using the so-called tracheid effect which is frequently used in both research and industry applications. However, a similar established method does not exist for measuring the out-of-plane angle, also known as diving angle. The purposes of this article were to evaluate if the tracheid effect can also be used to determine, with reasonable accuracy, the out-of-plane angle in Norway spruce and to verify an existing mathematical model used to calculate the fiber direction in the vicinity of knots. A newly developed laboratory laser scanner was applied for assessment of fiber directions in a single Norway spruce specimen containing a knot. It was assumed that the specimen had a plane of symmetry through the center of the knot, and by splitting the specimen through this plane into two parts, it was possible to make measurements on orthogonal planes. The results showed that the out-of-plane angle could not be determined with very high accuracy and the difficulties related to this objective were analyzed. Regarding the mathematical model of fiber direction in the vicinity of a knot, fiber directions calculated on the basis of this model agreed well with experimentally obtained fiber directions, but successful application of the model requires that the geometry of the knot is known in detail.


Keywords


Diving angle, fibre direction, knots, laser scanning, Norway spruce, tracheid effect

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References


Astrand E (1996) Automatic Inspection of Sawn Wood.

Doctoral thesis, Report no. 424. Department of Electrial

Engineering, Linkoping, Sweden.

Briggert A, Hu M, Olsson A, Oscarsson J (2016a) Evaluation

of three dimensional fibre orientation in Norway spruce

using a laboratory laser scanner. In Proc. World Conference

of Timber Engineering, August 22-25, Vienna,

Austria.

Briggert A, Olsson A, Oscarsson J (2016b) Three-dimensional

modelling of knots and pith location in Norway spruce

boards using tracheid-effect scanning. Eur J Wood Wood

Prod 74(5):725-739.

Dinwoodie JM (2000) Timber: Its nature and behavior, 2nd

edition. Taylor & Francis, New York, NY.

Ekevad M (2004) Method to compute fiber directions in

wood from computed tomography images. J Wood Sci 50:

-46.

Foley C (2003) Modeling the effects of knots in structural

timber. Doctoral thesis, Report TVBK-1027. Lund Institute

of Technology, Lund, Sweden.

Goodman JR, Bodig J (1978) Mathematical model of the

tension behavior of wood with knots and cross-grain. In

Proc. 1st International Conference on Wood Fracture,

August 14-16, Banff, AB, Canada.

Hankinson RL (1921) Investigation of crushing strength of

spruce at varying angles of grain. Air Service Information

Circular, 3(259), Material Section Report No. 130. US Air

Service, Washington, DC.

Hatayama Y (1984) A new estimation of structural lumber

considering the slope of grain around knots. Bulletin of the

Forestry and the Forest Products Research Institute, No.

:69-167, Japan (in Japanese).

Hu M, Olsson A, Johansson M, Oscarsson J, Serrano E

(2016) Assessment of a three-dimensional fiber orientation

model for timber. Wood Fiber Sci 48(4):1-20.

Hu M, Briggert A, Olsson A, Johansson M, Oscarsson J, S¨all

H (2017) Growth layer and fibre orientation around knots

in Norway spruce: A laboratory investigation. Wood Sci

Technol 52(1):7-27.

Kandler G, Fussl J, Serrano E, Eberhardsteiner J (2015)

Effective stiffness prediction of GLT beams based on

stiffness distributions of individual lamellas. Wood Sci

Technol 49:1101-1121.

Kandler G, Lukacevic M, F¨ussl J (2016) An algorithm for the

geometric reconstruction of knots within timber boards

based on fibre angle measurements. Constr Build Mater

:945-960.

Lukacevic L, Fussl J (2014) Numerical simulation tool for

wooden boards with a physically based approach to

identify structural failure. Eur J Wood Wood Prod 72:

-508.

Matthews PC, Beech BH (1976) Method and apparatus

for detecting timber defects. U.S. Patent no. 3976384.

Nystrom J (2003) Automatic measurement of fiber orientation

in softwoods by using the tracheid effect. Comput

Electron Agric 41:91-99.

Olsson A, Oscarsson J (2014) Three dimensional fibre

orientation models for wood based on laser scanning

utilizing the tracheid effect. In Proc. World Conference

on Timber Engineering, August 10-14, Quebec,

Canada.

Olsson A, Oscarsson J (2017) Strength grading on the basis

of laser scanning and dynamic excitation: A full scale

investigation of performance. Eur J Wood Wood Prod

(1):17-31.

Olsson A, Oscarsson J, Serrano E, K¨allsner B, Johansson

M, Enquist B (2013) Prediction of timber bending

strength and in-member cross-sectional stiffness variation

on the basis of local wood fibre orientation. Eur J Wood

Wood Prod 71(3):319-333.

Petersson H (2010) Use of optical and laser scanning

techniques as tools for obtaining improved FE-input

data for strength and shape stability analysis of wood

and timber. In Proc. V European Conference on Computational

Mechanics, May 16-21, Paris, France.

Philips GE, Bodig J, Goodman JR (1981) Flow-grain

analogy. Wood Fiber Sci 14(2):55-65.

Shigo AL (1997) A new tree biology: Facts, photos and

philosophies on trees and their problems and proper care.

Eight Printing, Shigo and Trees, Durham, NE.

Simonaho S-P, Palviainen J, Tolonen Y, Silvennoinen R

(2004) Determination of wood grain direction from laser

light scattering pattern. Opt Lasers Eng 41:95-103.

Soest J, Matthews P, Wilson B (1993) A simple optical

scanner for grain defects. Proc. 5th International Conference

on Scanning Technology & Process Control for the

Wood Products Industry, October 25-27, Atlanta, GA.

Viguier J, Bourreau D, Bocquet J-F, Pot G, Bl´eron L, Lanvin

J-D (2017) Modelling mechanical properties of spruce and

Douglas fir timber by means of X-ray and grain angle

measurements for strength grading purpose. Eur J Wood

Wood Prod 75:527-541.


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