A continuous ultrasonic scanner for lumber grading /

0.590 and 0.398 respectively. These two nondestructive

Bibliographic Details
Main Author: Mayhew, Stephen Allison, 1970-
Format: Thesis eBook
Language:English
Published: [Place of publication not identified] : [publisher not identified] ; 1996.
Subjects:
Online Access:Link to OAKTrust copy
Description
Summary:0.590 and 0.398 respectively. These two nondestructive
and MOE. The coefficient of determination (R) between the
and transverse vibration MOE were measured. Utrasonic stress
density to provide R2 values of 0.760 and 0.725 respectively.
grading technology through more accurate lumber strength and
improved by combining the ultrasonic variables with MOE and
in tension at a span of 3.35 m (11 ft). Multivariate
in.) x 152 mm (6 in.) x 5.49 m (18 ft) long No. 1, No. 2, and
information provided the highest R2 of 0.777. The average
knots, two growth characteristics which greatly affect
length of each sample with a prototype ultrasonic lumber
localized stress wave characteristics in lumber, 2) verify
No. 3 grade Southern Pine lumber. After the lumber had
potential for accurate prediction of lumber strength and
predict MOE. The W between the predicted and transverse
predicted and actual UTS using the MOE and density data was
prototype ultrasonic lumber scanning system to measure
provided a higher R2 of 0.658. The correlation was further
reached its equilibrium moisture content, the gross density
regression techniques were used to develop several
scanner. This scanner used a configuration of four 200 kHz
statistical models to predict ultimate tensile stress (UTS)
stiffness predictions. Specific objectives are: 1) develop a
stiffness, and information obtained from this research can be
strength and modulus of elasticity of Southern Pine lumber.
strength than MOE and density. Utrasonics show great
tensile strength. The lumber was then destructively tested
testing (NDT) variables form the basis for current state of
the art grading systems. The ultrasonic predictor variables
The goal of this research was to improve mechanical stress
The lumber sample contained 225 pieces of nominal 51 mm (2
The model combining the ultrasonics, density, and MOE
the use of ultrasonics for predicting the long-span tensile
transducers which were sensitive to slope of grain and edge
used for future development of an ultrasonic grading system.
variables were shown to be better predictors of lumber
vibration MOE was 0.839. In conclusion, the ultrasonic
wave travel times were automatically collected along the
weighted longitudinal velocity and density were used to
Item Description:"Major subject: Agricultural Engineering".
Vita.
Physical Description:x, 140 leaves : illustrations ; 28 cm.
Also available online.
Issued also on microfiche from Lange Micrographics.
Bibliography:Includes bibliographical references.