TY JOUR TI The role of the limit of proportionality in studying the properties of composite materials KW ultimate strength KW elastic limit KW proportional limit KW the application load KW load JO Actual directions of scientific researches of the XXI century: theory and practice AU Zobov, S.. AU Chernikov, E.A. PY 2014 IS 2 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov