TO DETERMINATION OF SOME DEFORMATIVE CRITICAL CHARACTERISTICS OF WOOD

Abstract

Wood and composite materials, products, parts, elements, structures based on it are and remain one of the main consumer products of various spheres of our lives, including construction, transport, engineering and shipbuilding, chemical, furniture, mining and aviation industries. Many of these materials work in compression along the fibers. The state of scientific researches of mechanical characteristics of continuous wood of deciduous and coniferous breeds and composite materials on their basis is analyzed in detail. Correct determination of the characteristics of mechanical properties involves experimental testing of solid wood of deciduous and coniferous species on instrumental testing machines in the rigid mode (by increasing displacement) by compression along the fibers. It is established that there are no methodologies for determining the mechanical characteristics in the supercritical stage of the material, ie on the descending branch of deformation. A methodology for determining the critical deformations of axial compression along the fibers of solid wood of deciduous and coniferous species, including elastic and plastic components, is proposed. This methodology has been tested on many species of wood that are grown in many countries around the world. A method for determining the ultimate deformations of wood and composite materials based on the analysis of the stress-strain state of the bending element of rectangular cross-section and diagrams of the mechanical state of the material "stress - strain". Further research on this issue is proposed, in particular the calculation of wooden elements and structures, taking into account the proposed methods.