The shear ramp: A new test method for the investigation of coated fabric shear behaviour – Part I: Theory

A new test method for the investigation of architectural coated fabric shear properties is proposed. The method relies on the biaxial pre-tensioning of the orthotropic specimen, where fibres are aligned with the loading directions. The shear deformation is enabled by means of linear stress ramps. In the first part of the paper, the theory behind the new test method is given. The shear stress distribution in a square plate loaded with a shear ramp is analytically calculated by means of Airy stress functions and by applying the Rayleigh–Ritz method. The difference between isotropic and orthotropic materials is investigated and compared to FEM results. Finally, a simple estimation of the shear stress in the sample is proposed.