Issue 51

E. Mousavian et alii, Frattura ed Integrità Strutturale, 51 (2020) 336-355; DOI: 10.3221/IGF-ESIS.51.25 343   ,lim ,lim cos α γ cosα b b b b j j j j j j N S H    (15)   ,lim ,lim sin α γ sinα b b b b j j j j j j T S H    (16) Taking into account that T b j, lim =  N b j, lim , the limiting hoop force resultant H b j, l im is:     ,lim μcos α γ sin α γ sin α μcosα b b b j j j j j b j j j S H          (17) So, the parallel sliding constraint can be formulated as: ,lim 1,lim b b b i j j H H H    (18) It should be observed that this constraint is more accurate than that proposed in the previous work [1] and therefore different results can be expected. (a) (b) Figure 7 : a) Resultant of the hoop stresses H i b per unit length of parallels passing through the corresponding control point at level z i and equilibrium diagram for forces per unit length of parallels; b) meridional forces at the two interfaces ( S j -1 b and S j b ) whose horizontal components are H j -1 b and H j b , respectively. Lastly, the optimization problem can be stated as follows: t /2 = Min max     2 2 b i i x z R         (19)