Change search
ReferencesLink to record
Permanent link

Direct link
Methods for collecting and analysing simultaneous strain and moisture data during wood drying
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
2002 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Improved understanding of moisture and mechanical behaviour is an international objective for wood drying research. The main objective of this licentiate thesis work was to develop an experimental method suitable for collecting valuable response data related to the moisture and mechanical behaviour of drying wood. Another objective was to provide an example on how multivariate methods can be used to analyse response data. A method for simultaneous non contact measuring of two dimensional surface deformations and interior densities have been developed. This was done using Digital Speckle Photography, DSP, and X-ray Computerised Tomography (CT). Displacements and densities were used for calculation of strains and moisture contents using a custom software developed in Matlab. Experimental tests of the measuring method were made on cross sections of Scots pine. The following accuracy was stated for different properties: - Displacements measured with DSP could be measured with a random error down to 0.01 pixels. A more typical calculated displacement error of approximately 10 micrometres, was found in paper I. - Strains derived from the displacements had a maximal error of 1.11 mstrain in an experimental test in paper II. - Accuracy in density measurements was expected to be less than +-6 kg/m3 for wet wood with moisture contents ranging from 6-100% and less than +-2 kg/m3 in dry wood, at a significance level of 0.05. This was estimated for a 2x2x1.5 mm3 measuring volume. - Moisture content measuring accuracy was estimated by simulations in paper II, which resulted in a measuring accuracy of +-1.8% moisture content at a significance level of 0.05 in a measuring volume with the approximate size of 2x2x1.5 mm3. A multivariate analysing method has been used to present an example on multivariate modelling of shrinkage behaviour in Radiata pine. The method was found to be an easy-to-use tool and useful for valid prediction of radial, tangential, longitudinal and volume shrinkage in the moisture range between 0% and 22% moisture content of the studied wood. The method also proved to be effective for untangling relationships between variables and generating information out of data. Finally, it can be stated that the developed measuring technique and the tested multivariate analysing method will be of use to improve the understanding of the behaviour of drying wood, focusing on moisture and mechanical properties.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2002. , 22 p.
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757 ; 2002:05
Research subject
Wood Physics
Identifiers
URN: urn:nbn:se:ltu:diva-17677Local ID: 49a0a5b0-c2ac-11db-9ea3-000ea68e967bOAI: oai:DiVA.org:ltu-17677DiVA: diva2:990682
Note
Godkänd; 2002; 20070222 (ysko)Available from: 2016-09-29 Created: 2016-09-29Bibliographically approved

Open Access in DiVA

fulltext(37749 kB)14 downloads
File information
File name FULLTEXT01.pdfFile size 37749 kBChecksum SHA-512
8c41da476451cd0f2d0d2b0b7384e38cdacb758eb637af8f734ff4921dab3503c2d3cc478010ad541124fac6995af3362453d5110e6929372939360f6300c875
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Danvind, Jonas
By organisation
Wood Science and Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 14 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 9 hits
ReferencesLink to record
Permanent link

Direct link