PASA tau_red = V_nucleo/(V - V_nucleo) = S^2/(Smax^2-S^2)
PASA sigma(u) = tau_red/2
PASA sigma^2/(2M) = (E0/2) tau^2 con E0=1/(4M)
PASA paralelo da u^2, no tau^2
PASA cinetico (dS)^2 = 0 y flexural (box S)^2 = 0 para S constante
PASA serie (tau^2): E0=4.2546, telon=1.06698, xi=19.6899
   paralelo (u^2): E0=9.6974 telon=1.13413 xi=15.6340
   serie   (tau^2): E0=4.2546 telon=1.06698 xi=19.6899
   u0 = Smin^2/Smax^2 = 0.2401  (margen compresible en S_min: 0.7599)
CONTROLES: 6/6
