Acoustic evaluation of wood properties

#Embodiments herein relate to the field of lumber manufacturing, and, more specifically, to methods, systems, and apparatuses for estimating the strength and/or stiffness of elongated wood workpieces based in part on acoustic data.

#Lumber—i.e., solid pieces of wood sawn from logs—is produced for a variety of uses. The suitability of a given piece of lumber for a particular use is partly a function of inherent characteristics such as wood type (e.g., hardwood vs. softwood), wood species, and natural defects (e.g., knots, rot, pitch pockets, compression wood, etc.), and characteristics introduced or influenced by the manufacturing process, such as the dimensions of the piece, moisture content, manufacturing defects, the locations of natural or manufacturing defects relative to the machined surfaces, and the like. Many of these characteristics affect the appearance, strength, stiffness, and other properties of lumber. As wood is a natural product, the properties of lumber can vary widely, even among pieces of lumber cut from the same log.

#Lumber is commonly graded according to established rules. Different sets of rules are applicable to different lumber types and intended uses. For example, in the context of softwood lumber, appearance lumber intended for decorative or non-structural use is often graded based on visual appearance, while ‘dimensional’ lumber intended for structural use is often graded based on mechanical properties that relate to strength. Stiffness, which is commonly expressed as a modulus of elasticity (MOE), has a known relationship to bending strength and is frequently used to estimate strength.

#Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

#FIGS. 1A-C illustrate a perspective view and plan views of an acoustic grading apparatus;

#FIGS. 2A-B illustrate perspective and front elevational views, respectively, of components of the apparatus of FIGS. 1A-C;

#In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

#Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order dependent.

#The description may use perspective-based descriptions such as up/down, back/front, and top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments.