The aim of this study was to create a reinforced composite wood-based panel that would be leaned towards the environment Plywood was used as a core material and fiber-reinforced polymer was used as a reinforcement. Conventional resin for the fiber-reinforced polymer was substituted with polyvinyl acetate (PVAC), which has several advantages, such as a lower price, easier handling, and better degradability. The second chosen component, basalt fiber, is cost attractive and environmentally friendly. The combination of one and two layers of fabric with three fiber fractions and 4 mm thick plywood was investigated. The best results were achieved with two layers of fabric and the highest fiber fraction. The improvements of the ultimate bending load and bending stiffness of the plywood in the perpendicular direction were 305% and 325%, respectively. The ultimate load and stiffness of the parallel direction were improved by 31% and 35%, respectively. However, specimens always failed in the compressional zone. The highest reinforcing effect was found with the impact test: The energy required to fracture specimens increased by 4213% and 6150% for one and two layers of fabric, respectively. In conclusion, specimens exhibited high ductility due to the PVAC and basalt fiber. The amount of work and energy required to cause fractures was extensive.

Sources of dynamic damping may be various. Mostly, the damping is implemented into calculations in a form of introduction of damping forces, as a product of the velocity vector and the damping matrix in an equation of motion. In practice, the damping matrix is usually assumed to be a linear combination of the mass matrix and the stiffness matrix (so called Rayleigh’s damping). This kind of damping primarily assumes the external environment viscosity as the source of damping, even though the part of Rayleigh's damping with the stiffness matrix implies the internal damping of the material. Explicitly, the internal viscosity of the material is respected using the appropriate material models. The relation between the Rayleigh damping and the Kelvin-Voight viscosity is shown in the paper. Dynamic damping occurs even when using non-elastic materials, where the unloading takes place in a different path from the loading and thus it leads to dissipation during loading cycles. The paper deals with the comparison of different types of damping of the oscillation of a building structure. The main aim of the paper is to recommend to apply the viscous material model instead of the obsolete and physically unjustified Rayleigh damping in the nonlinear dynamic time analysis of structures.

Cross-laminated timber (CLT) panels, composed of orthogonally bonded layers, are often used in civil engineering and tall constructions owing to their sustainability, prefabrication advantages and favourable mechanical performance. However, their multilayered, anisotropic and shear-compliant nature presents significant challenges for accurate structural modelling and performance prediction. This study presents an advanced numerical approach to analysing the bending behaviour of CLT panels using the finite element method (FEM) in combination with the classical laminate theory. The proposed plate model was implemented in FlexPDE and validated through a series of three-point bending experiments on three-layer spruce panels. Further verification was conducted using commercial FEM software—Dlubal, incorporating both linear elastic and non-linear damage models, and Abaqus, where a three-dimensional solid model with a cohesive zone formulation captured progressive delamination and local failure in the glued layers. Comparison of the experimental data and numerical simulations revealed strong agreement in load–deflection behaviour, stiffness evolution and damage localisation. The framework we developed accurately reproduces both the global and the local mechanical responses of CLT panels while maintaining computational efficiency. Our results confirm the reliability of laminate theory-based FEM formulations in the design, optimisation and safety assessment of cross-laminated timber structures in building applications.