Weyerhaeuser Company Limited

Steven M Cramer

Mark A Stanish

Stan L Floyd

A method for determining crook potential of wood is described. One embodiment comprises nondestructively obtaining lengthwise shrinkage rates (from a third party or by direct measurement) of wood and then determining crook potential of the wood based on the lengthwise shrinkage rates. Where the wood comprises lumber, lengthwise shrinkage rate measurements typically are made on at least one major planar surface of the lumber. The method typically comprises determining lengthwise shrinkage rates two or more measuring points separated by a predetermined distance, such as at substantially one-foot intervals along the lumber. Particular embodiments of the present invention determine lengthwise shrinkage rates using infrared radiation, microwave radiation, electricity, ultrasound energy, and combinations thereof Working embodiments of the method use ultrasound energy to determine lengthwise shrinkage rates. For example, one working embodiment measures the speed of an ultrasound pulse through wood to determine the modulus of elasticity (MOE) of the wood which can then be correlated to the lengthwise shrinkage rate. In another example, lengthwise shrinkage rate can be determined from the speed of an ultrasound pulse using an empirically derived formula, such as an exponential formula. Another embodiment of the present invention comprises determining crook potential of wood based on non-averaged lengthwise shrinkage rates. Another embodiment of the present invention comprises determining crook potential is determined using a finite element model (FEM). The method the present invention provides can determine crook potential that correlates with actual measured crook with an R,value of at least 0.5.

Method for determining crook potential in wood

A method for determining warp potential of wood. One embodiment comprises nondestructively obtaining lengthwise shrinkage rates and grain angles of wood&mdash;such as trees, logs, or lumber&mdash;then determining warp potential of the wood based on the lengthwise shrinkage rates and grain angles. The method typically comprises measuring plural lengthwise shrinkage rates and plural grain angles to determine warp potential. Where the wood comprises lumber, lengthwise shrinkage rate and grain angle measurements typically are made on at least one major planar surface of the lumber at at least two measuring points separated by a predetermined distance, such as at substantially one-foot intervals along the lumber. Particular embodiments of the present invention determine lengthwise shrinkage rates using electromagnetic energy, acoustic energy, and combinations thereof. Working embodiments of the method use ultrasound energy to determine lengthwise shrinkage rates and grain angles. Another embodiment of the present invention comprises providing a piece of wood having at least one major planar surface, positioning the piece of wood adjacent to a device for imparting energy through the piece of wood to determine at least one lengthwise shrinkage rate and at least one grain angle. Embodiments of the present invention are automated and can be adapted to industrial processes for commercial production of lumber or for forest management practices. Warp potential can be determined using a finite element model (FEM).

Method for determining warp potential in wood

A method for determining twist potential of wood is described. One embodiment of the method comprises nondestructively obtaining a grain angle of wood, such as trees or lumber, and then determining twist potential of the wood based on the grain angle. Where the wood comprises lumber, grain angle determinations typically are made on at least one major surface of the lumber. The method typically comprises determining grain angle at at least two measuring locations separated by a predetermined distance, such as at substantially one-foot intervals along the board. The method also can further comprise obtaining at least one fiber dive angle. Particular embodiments of the present invention determine grain angle using infrared radiation, microwave radiation, light energy (such as by using a laser), electricity, ultrasound energy, and combinations thereof. Working embodiments of the method used light energy and ultrasound energy to determine grain angle. For example, a first transmission speed of an ultrasound pulse through the board was determined along a first path and along a second path. Grain angle was then determined by comparing the first and second transmission speeds. Plural grain angles also can be determined using this ultrasound method. Twist potential can be correlated to empirically determined twist angle. The method of the present invention provides can determine twist potential that correlates with empirically determined twist potential with an R,value of at least 0.50.

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Lodi, WI, United States of America

Steven M Cramer