Performance optimization of CLT (NextGenCLT)
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Nowadays, the building and construction sector plays a significant role in energy
consumption, leading to a growing demand for sustainable solutions and material
optimization to reduce CO2 emissions. Cross-laminated timber (CLT) panels have
gained attention due to their lightweight and renewable nature, ease of
transportation and assembly, and excellent thermal and insulation properties.
However, considering the environmental and economic aspects, minimizing the
raw material usage in CLT panel production is crucial.
To investigate the effects of reducing material in the central part of a CLT panel
through the introduction of air gaps in the cross-layers, shear and four-point
bending tests were conducted on small and large samples produced in both a
university workshop and a CLT factory. The experimental results were compared
with FEM models created in MATLAB and ABAQUS.
The study focused on conducting shear tests on small specimens with five
different configurations of air gaps, analysing their dimensions and arrangement.
The deflection and bending capacity were compared with a solid CLT panel, with
specific attention given to two configurations featuring central air gaps but
differing in size.
The shear testing results of CLT panels with various air gap configurations
revealed that configuration with overlapping between cross layers demonstrated
the highest net rolling shear modulus and net shear strength. The amount of
overlap impacted material saving and net shear strength and increasing the air
gap size in centrally arranged configurations led to decreasing the net shear
strength.
From the four-point bending test, the analysis of different configurations reveals
that introducing air gaps with dimensions of 6 cm between cross layers leads to a
13% material reduction, which closely follows the bending stiffness of solid
specimens. However, increasing the air gap dimension to 12 cm shows a 19%
material reduction, but a significant decrease in bending stiffness is observed. The
deflection increases with wider air gaps, leading to reduced bending stiffness in
configuration with air gaps compared to solid panels. The results emphasize the
importance of accurately defining factors such as κs in calculating deflection and
bending stiffness, especially for panels with air gaps. Adjusting κs based on the
panel's geometry and air gap arrangement is crucial for accurate predictions.
Beskrivning
Ämne/nyckelord
Cross-laminated timber, CLT, material optimization, air gaps, shear strength, shear modulus, bending stiffness, strength test