A study of load-induced microdeformations within wood-based structural members using optical scanning techniques Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/p2676z35b

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Efficient use of wood in structural applications depends upon the accuracy with which we can predict the mechanical behavior of members under load. Most methods of lumber grading and laminated beam design depend upon statistical and/or empirical techniques in which averaged properties for complete members are derived. A knowledge of stresses and strains that develop locally within members as they are loaded would provide a more complete picture of the interactions that combine to affect the behavior of complete members. Wood's anisotropic, porous, and hygroscopic nature has limited the use of many conventional methods to experimentally obtain this information. This paper describes a technique for studying microdeformations within woodbased specimens under flexural loading in which computerised optical scanning (machine vision) is used. Specially prepared beams containing laminae of varying elastic moduli and defects were loaded nondestructively in thirdpoint flexure while being supported laterally to prevent buckling. Beam width was reduced to 0.25" to avoid significant gradients of strain perpendicular to the measured surface gradients of strain perpendicular to the measured surface. Displacements between horizontally arranged pairs of dots fixed to the beam's vertical surface were measured with a microcomputer-controlled video monitor. Digitized images of the dot positions prior to and after beam deflection were compared, and the distribution horizontal strains across the beam's vertical cross-section were calculated. Strain mappings in the vicinity of knot defects and of laminae of comparatively law elastic modulus were of substantially greater magnitude than predicted by simple elastic beam theory.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 24-bit Color) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2010-09-08T22:06:17Z (GMT) No. of bitstreams: 1 IrvingDavidC1989.pdf: 3263049 bytes, checksum: a41bba321d5622c30622a2682605a795 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2010-09-08T22:08:23Z (GMT) No. of bitstreams: 1 IrvingDavidC1989.pdf: 3263049 bytes, checksum: a41bba321d5622c30622a2682605a795 (MD5)
  • description.provenance : Made available in DSpace on 2010-09-08T22:08:23Z (GMT). No. of bitstreams: 1 IrvingDavidC1989.pdf: 3263049 bytes, checksum: a41bba321d5622c30622a2682605a795 (MD5)
  • description.provenance : Submitted by Nitin Mohan (mohanni@onid.orst.edu) on 2010-09-02T20:02:13Z No. of bitstreams: 1 IrvingDavidC1989.pdf: 3263049 bytes, checksum: a41bba321d5622c30622a2682605a795 (MD5)

Relationships

In Administrative Set:
Last modified: 08/14/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items