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60 MATERIALS MAR/APR 2025 FDM ASIA | www.fdmasia.com

Nicole Larkin performance compared to conventional spruce CLT, as well
as red maple and birch CLT, in terms of rolling shear strength.
The inclusion of maple lamellas in the outer layers of hybrid
CLT enhanced its load-carrying capacity during bending tests.

The homogenous poplar CLT exhibited Emg, fm, and fr
values nearly equivalent to or better than those of spruce
CLT, thereby indicating its potential application in load-bearing
structures and as a viable alternative for CLT production. The
production of CLT presents a promising opportunity for the
value-added utilisation of poplar.
Both the adhesive type and wood species had a significant
of 0.65 between wood and steel. impact on the bending strength (fm), global bending modulus
The CLT panels and auxiliary components, such as (Emg), and rolling shear strength (fr) independently; however,

steel loading rollers and supports, were represented using their interaction effect was not found to be significant.
SOLID186 elements. 1C-PUR adhesive outperformed the ME in terms of global
All 20 element nodes have three degrees of freedom, bending modulus, bending strength, and rolling shear strength.
allowing strain, deflection, hyperelasticity, creep, and stress For homogeneous poplar and spruce CLT, a 19 percent
stiffening in all three dimensions. A single homogeneous unit variation in bending stiffness was observed between the
represents the loads and supports at both ends and the middle. theoretical and experimental values, whereas a 12 percent
This simulation employed boundary conditions like the variation was noted for hybrid CLT, with the modified gamma

experiment depicted. A hinged or fixed support inhibiting the approach yielding the most accurate results.
displacement and roller support allowing X-axis movement Furthermore, the theoretical approaches indicated a 6.5
were given for each CLT panel at the end, and two rollers percent reduction in rolling shear strength and a 4.5 percent
loaded the top layer, identical to the experiment. The auto- overestimation of bending strength, with the shear analogy
generated shared topology was used to create the mesh. The yielding the most precise result.
CLT models were loaded with a load of 21,500 N for both The bending stiffness of hybrid CLT, as per FEM, was
FA and FB, as determined in the experiment. approximately 11 percent lower than the experimental values,
whereas, for both poplar and spruce CLT, the difference was
Conclusions Of The Experiment between six to eight percent.

Bending and shear properties of poplar and maple–poplar In summary, the bending and rolling shear performance
hybrid CLT were compared to conventional spruce CLT using of both poplar hybrid CLT (maple–poplar) outperformed the
experimental, analytical, and FEMs. The primary findings are traditional spruce CLT serving as a foundation for encouraging
as follows: the use of low-grade poplar, and maple as the primary wood
The hybrid CLT, involving high-density outer maple layers species for both homogenous and hybrid CLT production.
and a poplar core layer, resulted in significant increases in This study was also designed to expand the market for
Emg, fm, and fr by 74 percent, 37 percent, and 48 percent, low-value hardwood species like poplar, and maple, which

respectively, compared to homogeneous poplar CLT. are primarily used in lower value-added products. FDM
Additionally, the hybrid CLT also demonstrated superior ENQUIRY NO. 2202