Graduate Thesis Or Dissertation
 

A study of the coefficient of drag resistance in yarding logs

Öffentlich Deposited

Herunterladbarer Inhalt

PDF Herunterladen
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/pg15bh55v

Descriptions

Attribute NameValues
Creator
Abstract
  • This study was conducted to examine the coefficient of drag resistance (µ) between a log and bare forest soil during partial suspension yarding. Drag resistance in this study was defined as the resistance due to friction between the soil and the log plus the resistance due to the plowing action of the log in the soil. The coefficient of drag resistance is the ratio of the drag resistance forces parallel to the ground and the normal support force between the log and the ground. Data were collected on four test plots on Paul Dunn and McDonald State Forests located in the foothills of the Coast Range in Oregon. A photographic technique was developed to measure the value of the drag resistance coefficient during yarding. This method used angles measured from a photograph of a yarded log and the logs dimensions to ca1cu1ate µ. The method is based on the equilibrium of the forces on the log at the instant the photographic sample was taken. Data were taken to determine both the static and dynamic drag resistance coefficient for uphill yarding of young growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) logs. Regression equations were developed to predict the static µ as a function of log geometry, ground slope, soil texture, soil moisture, and soil density. These equations suggest that soil moisture and ground slope are the most significant variables in explaining µ, with log geometry, soil texture and soil density playing a less important role. The equations developed were verified using a chi-square test for goodness-of-fit to compare predicted and observed values of µ on additional data. Analysis of the data collected for the dynamic drag resistance coefficient revealed that the assumptions of the measurement method were violated so no regression equations were developed. Suggestions were given on the conditions required for the method to work. A load factor was developed which indicates the increase in log load capacity for a skyline logging system when dragging rather than flying a log load. The calculations for the load factor were based on the results of the study.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Urheberrechts-Erklärung
Publisher
Language
Digitization Specifications
  • Master files scanned at 600 ppi (256 Grayscale) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 ppi (256 B+W), using Capture Perfect 3.0, on a Canon DR-9080C. CVista PdfCompressor 3.1 was used for pdf compression and textual OCR.
Replaces

Beziehungen

Parents:

This work has no parents.

In Collection:

Artikel

Miniaturansicht Titel Hochladedatum Sichtbarkeit Aktionen
file details Henshaw__John_MS.pdf 2017-08-08 Öffentlich Herunterladen