“…1 *t]~ n' ') = fi~ ~' ') (n = 1, 2; l = 0, 2, 3, ...). The coefficients ~" 1) (r/ = 1, 2) are expressed m terms of u~ °' ) -(2,1) Ul-(I' 1) -----_152ikq~t~o, 1) + ~{1, 1), fi(12, 1) = _ 151eiq~)Xfi~O, 1) + Ul is introduced which characterizes the stresses (in the linear approximation, see [5]) which arise in the middle layer when an element of its area is changed.…”