On the Design Process of Tensile Structures 9 E1111 E222 E1122 C Fig.11.Young's Moduli and Poisson ratio as function of the fabric strain,PVC coated fabric [19] This set of 4 equations serves a non linear system of equations for the four unknown values e1,e2,kI,kz.After solving the equations the stresses of the fabric can be defined directly by 711 and √1+km 022= 1+m The calculated strains and stresses enable to define the stiffness E1111,E2222 and E1122.The elastic stiffness are non linear and closely related to the strain ratio in warp and fill direction.Even the Poisson ratio E1122 is non linear and depending to the strain ratio of the yarns. The numerical process of reassembling enables taking into account the behaviour of the fabric,the influence of the seams and the distribution of the tension stress through the whole surface.The plane strips have to be remeshed,sewed together and pretensioned by moving the sewed structure into defined boundaries,moving support points into their position after reassembling or putting internal pressure onto the system.The stress distribution and geometry of the sewed and pretensioned structure is different from the assumed stress distribution of the shape of equilibrium. The differences are depending on the curvature of the surface,the orientation of the strips in relation to the main curvature,the torsion of the strips,the distortion of the load transfer along the seams,the stiffness of the seams,the assumed compensation of the flatten strips,the width of the strips,the of the surface,the shear deformation of yarns and in the shown example of the load transfer between the boundary cables and fabric,see Fig.12. In the shown example the stress distributions varies in a single strip and changes from strip to strip.Relatively low tension stress in the middle strip can been see as result of less compensation.The influence of the stiffness of the seams can be shown in the difference between deformation in vertical direction comparing the geometry of the shape of equilibrium and reassembled and pretensioned structure.For the shown example the difference is app.20%of the span.The antimetric deformation is caused by the inhomogeneous stress distribution in the cross section along the high points.The tension stress perpendicular are unsteady,low stress leads to high vertical deformations and high stress kept the fabric down which can clearly seen in the up and down of the differences.On the Design Process of Tensile Structures 9 Fig. 11. Young’s Moduli and Poisson ratio as function of the fabric strain, PVC coated fabric [19] This set of 4 equations serves a non linear system of equations for the four unknown values ε1, ε2, k1, k2. After solving the equations the stresses of the fabric can be defined directly by σ11 = 1 L2  F1 1 + k2 1m2 1 and σ22 = 1 L1  F2 1 + k2 2m2 2 The calculated strains and stresses enable to define the stiffness E1111, E2222 and E1122. The elastic stiffness are non linear and closely related to the strain ratio in warp and fill direction. Even the Poisson ratio E1122 is non linear and depending to the strain ratio of the yarns. The numerical process of reassembling enables taking into account the behaviour of the fabric, the influence of the seams and the distribution of the tension stress through the whole surface. The plane strips have to be remeshed, sewed together and pretensioned by moving the sewed structure into defined boundaries, moving support points into their position after reassembling or putting internal pressure onto the system. The stress distribution and geometry of the sewed and pretensioned structure is different from the assumed stress distribution of the shape of equilibrium. The differences are depending on the curvature of the surface, the orientation of the strips in relation to the main curvature, the torsion of the strips, the distortion of the load transfer along the seams, the stiffness of the seams, the assumed compensation of the flatten strips, the width of the strips, the of the surface, the shear deformation of yarns and in the shown example of the load transfer between the boundary cables and fabric, see Fig. 12. In the shown example the stress distributions varies in a single strip and changes from strip to strip. Relatively low tension stress in the middle strip can been see as result of less compensation. The influence of the stiffness of the seams can be shown in the difference between deformation in vertical direction comparing the geometry of the shape of equilibrium and reassembled and pretensioned structure. For the shown example the difference is app. 20% of the span. The antimetric deformation is caused by the inhomogeneous stress distribution in the cross section along the high points. The tension stress perpendicular are unsteady, low stress leads to high vertical deformations and high stress kept the fabric down which can clearly seen in the up and down of the differences. U22 E2222 U22 E1122 U U22 U11 E1111