Thesis
Pressure Prediction Model in Cross Laminated Timber Manufacturing for Low-Quality Lumber
Washington State University
Master of Science (MS), Washington State University
2021
DOI:
https://doi.org/10.7273/000005525
Abstract
Cross Laminated Timber (CLT) has been considered a feasible and sustainable option as a building material due to its advantageous mechanical properties, and for being a renewable resource with an extraordinary construction market in the coming years. Although there is an increasing demand for eco-friendly products such as CLT, a significant quantity of lumber has been neglected and tagged as out-of-grade material after visual grading. Low-quality timber has proved to be efficient when used in combination with high-grade materials for CLT panels as long as it does not require high-structural performance. However, because defects are said to prevent the lumber be flat during panel consolidation, wood with out-of-plane defects have been perceived as a problem to be avoided. This thesis proposes a reasonable model, based on mechanics of materials, that is capable of estimating the required pressure that can ensure intimate contact between layers of lumber during CLT manufacturing. The experimental and theoretical pressures were found to be no more than 45 kPa for the SPF samples used in this study, which is significantly less than 690 kPa, a standard pressure used by manufacturers. This new knowledge is an important step to reduce rejection rate of perceived low-quality lumber due to defects, such as twist, bow and cup by the wood industry as a CLT feedstock, especially in the case of lumber from small diameter timber (SDT). The use of planer machines to minimize cup deflections was critical to compress samples with the pressure values obtained in this investigation and successfully make lumber flat. Furthermore, shear and delamination tests indicate out-of-plane defects tend to not cause any relevant bonding issues for pressure application of 414 kPa. As a desired outcome of this study, the implementation of this pressure model could reduce losses and optimize industrial manufacturing process by expanding the use of low-quality materials such as SDT, positively impacting the wildfires on the west coast and creating economic growth opportunities.
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Details
- Title
- Pressure Prediction Model in Cross Laminated Timber Manufacturing for Low-Quality Lumber
- Creators
- Dalisson Peterson Silva do Carmo
- Contributors
- Karl Englund (Advisor)Donald Bender (Committee Member)Vikram Yadama (Committee Member)Hui Li (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 159
- Identifiers
- 99901051427201842
- Language
- English
- Resource Type
- Thesis