Modified hydraulic bulging in acquisition of stress strain curve

From classical hydraulic bulging of a circular diaphragm, a new method of recording a stress-strain curve is derived named modified hydraulic bulging on the sphere. New method allows more accurate determination of membrane stress in the deforming material. Assumption on the bulk geometry is no longer needed since modification, using sphere as an obstacle, determines the radius of curvature needed in acquisition of membrane stress. Performing modified hydraulic bulging upon just one test specimen, yields thee points of stress-strain curve. Experimentally obtained points have different strains, covering different areas ; small, medium and large deformations, within a single experiment. Use of the small transducer integrated in apparatus, enables acquisition of force and thus reliable stress acquisition upon the known (spherical) geometry. Likewise obtained stress-strain curve was used in creation of FE model of the modified hydraulic bulging on the sphere.