TO DETERMINATION OF CRITICAL DEFORMATIONS OF CONIFEROUS AND DECIDUOUS TIMBER SPECIES

Abstract

The article analyzes in detail the literary sources for determining the critical deformations of various hardwood and coniferous wood species by domestic and foreign scientists. By analyzing the works of different researchers, it was found that the critical deformations of pine wood were experimentally determined by Tuturin S.V. and Varenyk K.A. on samples of structural sizes of different sections in rigid test mode (by increments of displacements). It was also found that the critical deformations of wood were theoretically obtained by Grinkrug N.V. based on the analysis of experimental studies of different scientists. This dependence is empirical and depends only on the boundary stresses.For the first time, we have carried out detailed experimental studies of various conifers (larch, pine, spruce) and hardwood (birch, alder, ash) species of wood for compression along fibers under a single short-term load. Based on these studies, complete wood deformation diagrams were drawn and critical deformations of all the species studied were determined.A universal formula for theoretical determining of the critical deformations of any species of wood was also obtained. The convergence of our dependence and the function proposed by Grinkrug N.V. is carried out on the basis of experimental data of different authors. Our function has been found to have much better convergence. It was found that the main advantages of our dependence are: simplicity and convenience in calculations, it distinguishes two components (elastic and plastic), is not empirical, depends on the maximum tension and the initial modulus of elasticity; can be used for both coniferous and deciduous wood. And in the future it will be used for all kinds of calculations of elements and structures from wood.