Fig. (7) In (a), schematic picture of the projected stress field corresponding to the stress function (17): here A = a²/(8(h² − hh₁ − hh₂ + 2h₁h₂)), B = b²/(8(h² − hh₁ − hh₂ + 2h₁h₂)), . In (b) schematic picture of the projected stress field corresponding to the stress function (17), in the case study; the load per unit area p must be given in kNm^-2, and the projected stress components, are generalized stresses which read in kNm^-1. In (c), plot of the projected axial force along the diagonals (dashed line) and of the axial force along the fold (solid line), as a function of x₁, in the interval [−a/2, a/2].