Sustainable materials such as cross-laminated timbers (CLT) are increasingly being used in the
construction of green buildings worldwide. Such products may be exposed to cyclic environmental
conditions and exhibit moisture-induced damage. The main objective of this study is to develop
and validate an efficient, physically-based tool to simulate the moisture transport, and
consequently moisture-induced stresses and deformation in laminated orthotopic composites.
Predicting the moisture profile variation with time is the first step toward understanding the
performance of CLT panels under extreme environmental loads. A comprehensive literature
review was conducted to determine the most critical parameters in moisture transport phenomena
in CLT panels to ensure the capability of the framework to capture the essential moisture transport
mechanisms. Thermal moisture analogy theory was used for simulating the moisture transport
across the composite material cross-section. Unlike previous studies, the moisture adsorption curve
of the material was used instead of employing the surface emission coefficient to estimate moisture
flux at the surfaces. The method was verified and validated based on a simple one-dimensional (1-D) analytical model and experimental data, respectively. A series of parametric studies were
conducted using the validated model to highlight the effect of glue lines, wood species, boundary
conditions, panel dimension, and orientation of CLT layers on the moisture transport across the
composite panel.
After predicting the moisture profile of CLT panels, the numerical model was used to determine
the stresses caused by humidity differences on panel surfaces. The applied transient load in the
model was obtained from the moisture transport simulation. The total strain rate is assumed as the
sum of the elastic and the moisture-induced strain rate. The mechano-sorptive strain is omitted
from the material model since it is assumed that samples are not under mechanical loading. The
stress model was successfully validated by experimental data reported in the literature. Parametric
studies were conducted to investigate the significant role of panel bonding lines (i.e. elasticity
modulus and moisture diffusivity) on moisture-induced stresses. A failure analysis was completed
to determine how wood species affect laminated composite failure. The same approach was
followed to determine the moisture-induced deformation through a finite element analysis. Finally,
the effect of adhesive elasticity and its moisture diffusivity on the deformed shape of CLT panels
was investigated parametrically. This study showed that the choice of adhesive along with the combination of wood species, could significantly affect the panel’s moisture profile and developed
stresses even after 14 days under similar environmental conditions. As demonstrated in this thesis,
simulating moisture transport in CLT panels is crucial in determining stresses and deformation
caused by environmental conditions. / Graduate / 2023-12-01
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/14553 |
| Date | 06 December 2022 |
| Creators | Afshari, Zahra |
| Contributors | Malek, Sardar |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Available to the World Wide Web |
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