Issue 42

M. Olzak et alii, Frattura ed Integrità Strutturale, 42 (2017) 46-55; DOI: 10.3221/IGF-ESIS.42.06 50 p p p p 3 3 i 1 i i i 1 h h 1 1 s s s s i i Δh i 1 i i i 1 i 2 2 12 s s Δt i 1 i 1 2                (2) where: h h i 1 i h 1 i 2 2    ; h h i i 1 h 1 i 2 2     ; After transformation and substitution for Δh i v i Δt  being the velocity of crack faces motion we have   3 3 3 3 h h h h 1 1 1 1 i i i i 2 2 2 2 p p p 6 η v s s i 1 i i 1 i i 1 i 1 s s s s s s s s i i 1 i 1 i i i 1 i 1 i                                         (3) The discrete boundary conditions have the form p 1 = p amb p n = p n-1 After writing Eq (3) for all sections of the crack we obtain the following set of linear equations with a 3-diagonal matrix p B A D 1 1 1 1 p C B A D 2 2 2 2 2 C B A D p n 1 n 1 n 1 n 1 n 1 C B D n n n p n                                                                                     (4) where: 3 A h i 1 i 2   3 C h i 1 i 2   3 3 B h h i 1 1 i i 2 2                D 6 η v s s i i i 1 i 1        and from the boundary conditions we have