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

pixabay shear by 12 percent compared to low-density CLT panels
made from Chinese fir.
Ma et al. reported that hybrid maple–spruce CLT (Acer
saccharum–Picea glauca) exhibits a 28 percent greater

modulus of elasticity compared to hybrid spruce–maple CLT
while demonstrating a 24 percent reduction in rolling shear
strength due to the lower rolling shear modulus of the core
spruce wood.
The core beech layer enhanced the rolling shear performance
of hybrid spruce–beech CLT nearly threefold compared to
spruce CLT, as reported by Aicher et al., and 1.8 times greater
In hybrid CLT panels, high-density outer layers enhance than laminated strand lumber (LSL).
bending performance, whereas core layers augment shear

performance. Function Of Theoretical Methodologies And The Finite
Consequently, designers of hybrid CLT panels must assess Element Method (FEM)
the influence of the outer and core layers on ultimate load Theoretical methodologies (shear analogies, modified gamma,
capacity and serviceability. Timoshenko beam theory, and composite theory) alongside the
Hematabadi et al. reported that low-density poplar (Populus finite element method (FEM) are effective means of analysing
alba) CLT exhibited reduced Emg relative to larch and pine; the bending performance of CLT panels .
however, a high-density beech (Fagus orientalis) core layer Compared to experimental data, the shear analogy

with poplar outer layers enhanced bending performance by forecasts a 25 percent reduced bending stiffness for white
12.5 percent and rolling shear by 30 percent. ash and red maple CLT.
In a similar vein, Sciomenta et al. observed an increase At the same time, He et al. reported that the effective
in bending (37 percent) and rolling shear performance (24 bending stiffness via shear analogy (EIeff, shear) yielded the
percent) in hybrid beech-Corsican pine (Fagus sylvatica–Pinus most precise result for local bending stiffness (EIl). In contrast,
nigra) CLT compared to the homogeneous Corsican pine CLT, modified gamma theory (EIeff, gamma) was more accurate
attributed to the superior density and rolling shear modulus for global bending stiffness (EIg).
of beech wood. The authors further observed that FEM could evaluate the
Furthermore, melamine–urea–formaldehyde (MUF) adhesive stiffness and strength of CLT panels with a range of 10–20

demonstrated enhanced performance relative to polyurethane percent accuracy. Shear analogies showed higher precision for
(PUR). bending and rolling shear strength, whereas bending stiffness
In a separate investigation, Lu et al. indicated that hybrid was the gamma method.
poplar–Douglas fir CLT exhibited approximately 8 percent Huang et al. reported that the composite beam theory
greater bending stiffness, whereas hybrid Douglas fir–poplar and shear analogy technique yield precise findings for fr in
CLT showed 22 percent enhanced bending stiffness compared the context of out-of-plane bending; however, the modified
to pure poplar CLT. gamma method demonstrates excellent reliability with the

Yin et al. observed that the high-density outer layer redesigned planar configuration.
enhanced bending performance by 15 percent and rolling Dobeš et al. noted that the FEM forecasted a maximum