Issue 51

S. Merdaci et alii, Frattura ed Integrità Strutturale, 51 (2020) 199-214; DOI: 10.3221/IGF-ESIS.51.16 203   0 0 0 0 b b b b b b s s x x y y xy xy x x y y xy xy x x s s s s s s s s y y xy xy yz yz xz xz b N N N M k M k M k M k M k M k S S d q w ws d                                           (10) where the stress resultants N, M, and S are defined by   /2 ( ) /2 , , 1 , , , , , ( ) , , x y xy h n b b b x y xy x y xy h s s s x y xy N N N M M M z dz f z M M M                                    /2 ( ) /2 , , ( ) . h n s s xz yz xz yz h S S g z dz       (11) where A is the top surface, and the stress resultants N, M, and s are defined by: , , s b s b s s s s s s N A B B M A D D k S A M B D H k                                     (12) 0 12 11 12 11 12 11 0 12 22 12 22 12 22 11 12 11 12 11 12 12 22 12 22 12 22 11 12 11 12 11 12 12 22 12 22 12 22 s s x x s s y y b b s s x x b s s y s s s s s s s x s s s s s s s y N B B B A A B N A A B B B B M B B D k D D D M k B B D D D D M B B D D H H M B B D D H H                                                 0 11 66 66 66 66 66 66 66 66 44 55 0 0 b y s x s y s xy xy b s b xy xy s s s s s xy xy s s yz yz s s xz xz k k N A B B M B D D k B D H M k S A A S                                                                                                (13) where Aij , Bij , etc. are the plate stiffness defined by   1 11 11 11 11 11 11 3 ( ) 2 2 ( ) 12 12 12 12 12 12 11 1 ( ) 66 66 66 66 66 66 1 1, , , ( ), ( ), ( ) 1 2 n n s s s h s s s n n n h s s s n A B D B D H A B D B D H Q z z f z z f z f z dz A B D B D H                                       (14a)     ( ) 22 22 22 22 22 22 11 11 11 11 11 11 11 2 ( ) , , , , , , , , , , , 1 s s s s s s n E z A B D B D H A B D B D H Q     (14b)     1 3 2 44 55 1 ( ) ( ) , 2 1 n n h s s n h E z A A g z dz         (14c)