This article discusses numerical modeling of a plywood roof panel based on a finite element model. The modeling of the panel skins was performed taking into account the orthotropy of the plywood. When calculating the roof panel's deformability, it is necessary to account for the reduction in structural rigidity during operation by introducing a reduction factor. A computational study of the roof structure's deformability allowed us to establish a coefficient for the utilization of the roof panel's cross-section rigidity.

Keywords: plywood roofing board, glued laminated board element, modulus of elasticity, volumetric density, Poisson's ratio, design span, standard load, four-node finite element, section moment of inertia

The article discusses the method for calculating beams with corrugated walls as three-layer structures of equivalent rigidity. The derivation of resolving equations for a one-dimensional finite element of a three-layer beam is given. A hypothesis is introduced that the shelves fully perceive normal stresses, and the wall only works on shear. When obtaining the basic equations, forced deformations are taken into account, which may include creep deformations, temperature deformations, shrinkage deformations, etc. The solution of the test problem for a beam hinged at the ends under the action of a load uniformly distributed over the length is presented. To control the reliability of the results, a finite element analysis was performed in a three-dimensional formulation in the LIRA software package. Shelves of the beam are modeled by flat triangular shell finite elements, and the wall is modeled by rectangular shell FE.

Keywords: corrugated wall beam, three-layer beam, finite element method, equivalent rigidity, stress-strain state