Issue 31

E.M. Nurullaev et alii, Frattura ed Integrità Strutturale, 31 (2015) 120-126; DOI: 10.3221/IGF-ESIS.31.09 122 Сonsidering W ( J, ) and α (mm) to be variable and denoting the combination of the rest alphabetic and digital characters as constants C 1 and C 2 from the expression (2) we get the following: 2 1 3 1 1 1.25 1 m ch r m C RT                      2 3 1 2 29 0.225 10 g C exp T T a               which allows us to write the dependence (2) in compact form:    1 2 1 2 1 1 b W C C d            (3) The Eq. (3) can be solved by means of Table of Standard Integrals [10]: 2 3 1 1 2 1 1 2 1 1 1 1 b b b b W C d C C d C d C C d                      Further, as a result of integration and algebraic transformations, we obtain the equation: 3 3 2 1 1 2 2 3 2 2 3 1 2 2 b b b b b b W C C C                         (4) which leads, using the notations in (2), to the required dependence of the mechanical fracture energy of PCM on its basic formulation parameters:   2 3 3 2 1 2 3 1 3 3 2 2 3 1 1 1.25 29exp  0.225 10 2 2 1 m b b b b ch r g b m W RT T T a                                                                  (5) Let us note that the mechanical fracture energy ( W ( J )), is equal to zero when α b =1, indicating at its required normability. U LTIMATE ELONGATION AND ENERGY TO BREAK ltimate values of relative elongation (α b (mm)), as well as strain (ε b (%)), can be estimated by considering the velocity and degree of strain of an average polymeric binder layer between the solid particles of the filler [7]: 3 3 0 0 3 3 0 3 1 1 1 f m m f b b m m f b b m a a                                          (6) where the indices «f» and " 0 " refer to the filled and free states of the 3D cross-linked plasticized polymer binder of PCM. For engineering use of the Eq. (5) when developing new PCMs based on 3D cross-linked plasticized elastomers it is necessary to know the value of the maximum relative elongation or ruptural deformation of the polymeric binder. As follows from the relation (1), the values of 0 b  ( mm ) or 0 b  (%) are determined by the polymer volume fraction in the plasticized binder ( φ r ( vol. fraction )), effective concentration of transverse bonds ( ν eff (mol/cm 3 ) ), comprising permanent U