Issue 47

E. Mele et alii, Frattura ed Integrità Strutturale, 47 (2019) 186-208; DOI: 10.3221/IGF-ESIS.47.15 196 Therefore the shear stiffnesses of the hexagrid, G * 12H and G * 21H , normalised to the shear modulus of the member solid material, G s , are given by:   5 h 1 13 h * 3 12,H d 11 2 s 1 5 2 s h h h I A h 1 G 12I (1 ν) h dCosθ h 6E G bdh Senθ A h 24I (1 ν)χ                                 (15) 3 13 d 5 d 4 11 2 2 d s 3 2 d d d * 21,H 5 s 2 3 13 d 5 d 4 11 2Cos θ d I 2 A d 1 d 6I Sen θ 6E A d 24I (1 ν)χ G 4(1 ν)Sen θ G b( h dCos θ)d Sen θ d I 1 2 -A d Cos θ Cos θ 2 d                                                                                                                  (16) where: I h is the inertia of the cross sectional area of the horizontal beam with respect to the flexural axis, and:   2 2 h h d d d h 1 3 2 s 11 12 2 I I A d Sen θ I d 36E                 2 d d h 2 13 3 3 A Sen θ d 2h Cos θ d              d d h h 11 12 3 3 2 2 2 d h 13 s 2I Cos θ 2I Cos θ I I , h d h d 8I 4I 2E d h                The Eqs. (13-15) and Eq. (16) only contains geometrical quantities, i.e. the geometrical characteristics of the grid (  , h, d), and the geometrical properties of the structural member cross sections (A h , A d , I h , I d , χ h , χ d ). Therefore E * 1H /E s , E * 2H /E s , 3 h d d h d h d d 3 3 3 2 s 11 12 2 d I A d I Cosθ d I Cosθ 2A I h h Cosθ 36E             2 2 d d h h h d 2 2 h h h d d d 12A d I Cosθ 12A h I Cosθ , A h 24I (1 ν) χ A d 24I (1 ν) χ        