The effect of thickness of transverse and longitudinal layers on deformability and stress distribution in three-layer panels made of cross-laminated timber

Abstract

Introduction. The key feature of timber and materials, made from it, is anisotropy, or a pronounced difference between mechanical properties manifested in different directions. The construction of a cross-laminated timber plate, or a CLT panel, ensures its high strength and rigidity due to the perpendicular arrangement of fibers in mutually perpendicular layers. The article examines the effect of thickness of transverse and longitudinal layers on deformability and stress distribution in three-layer CLT panels. The relevance of the work lies in the need to obtain computational data for analyzing changes in strength characteristics of panels to select the most effective panel configuration. Materials and methods. Due to the lack of a standardized testing methodology, SCAD+ software package was applied to conduct the studies using numerical methods. The design scheme is identified as a general system whose deformations and principal unknowns are represented by linear displacements of nodal points along the X, Y, Z axes and rotations around these axes. A three–layer plate was selected as the element to be analyzed, the outer layers of which are longitudinal, and the inner one is transverse. Its simplified design scheme is a hinged beam. Results. The results of the study and calculations made using SCAD+ were applied to make tables and graphs showing dependence of deflection, distribution of normal and shear stresses on thickness of transverse and longitudinal layers of timber. Conclusions. The data, obtained by the authors, allow evaluating the effect of thickness on deformability and stress distribution in three-layer CLT panels to select the effective design. A change in thickness does not always bring a large difference between mechanical properties, which allows optimizing the panel parameters. The significance of the research lies, among other things, in expanding the scientific and engineering knowledge of timber structures.